WO2014198669A1 - An oxygen sensitive material, and use thereof to sense oxygen in three-dimensional spaces - Google Patents
An oxygen sensitive material, and use thereof to sense oxygen in three-dimensional spaces Download PDFInfo
- Publication number
- WO2014198669A1 WO2014198669A1 PCT/EP2014/061857 EP2014061857W WO2014198669A1 WO 2014198669 A1 WO2014198669 A1 WO 2014198669A1 EP 2014061857 W EP2014061857 W EP 2014061857W WO 2014198669 A1 WO2014198669 A1 WO 2014198669A1
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- Prior art keywords
- oxygen
- probe
- scaffolding
- microporous
- dye
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- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 title claims abstract description 123
- 229910052760 oxygen Inorganic materials 0.000 title claims abstract description 123
- 239000001301 oxygen Substances 0.000 title claims abstract description 123
- 239000000463 material Substances 0.000 title claims abstract description 104
- 239000000523 sample Substances 0.000 claims abstract description 180
- 230000002209 hydrophobic effect Effects 0.000 claims abstract description 31
- 229920000642 polymer Polymers 0.000 claims abstract description 27
- 238000004113 cell culture Methods 0.000 claims abstract description 12
- 238000009826 distribution Methods 0.000 claims abstract description 12
- 229920001600 hydrophobic polymer Polymers 0.000 claims abstract description 10
- 238000012360 testing method Methods 0.000 claims description 53
- 230000005855 radiation Effects 0.000 claims description 52
- 238000005259 measurement Methods 0.000 claims description 43
- 238000000034 method Methods 0.000 claims description 42
- 210000004027 cell Anatomy 0.000 claims description 41
- 230000005284 excitation Effects 0.000 claims description 27
- 239000003960 organic solvent Substances 0.000 claims description 25
- 239000012528 membrane Substances 0.000 claims description 22
- 238000006243 chemical reaction Methods 0.000 claims description 20
- 239000011148 porous material Substances 0.000 claims description 17
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 14
- 238000004891 communication Methods 0.000 claims description 13
- 239000012530 fluid Substances 0.000 claims description 13
- -1 polyethylene Polymers 0.000 claims description 13
- 230000008859 change Effects 0.000 claims description 11
- 230000003287 optical effect Effects 0.000 claims description 11
- 238000005424 photoluminescence Methods 0.000 claims description 11
- 238000012544 monitoring process Methods 0.000 claims description 10
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 claims description 9
- 238000012258 culturing Methods 0.000 claims description 9
- 230000000779 depleting effect Effects 0.000 claims description 9
- 239000004793 Polystyrene Substances 0.000 claims description 8
- 150000001732 carboxylic acid derivatives Chemical group 0.000 claims description 8
- 238000004519 manufacturing process Methods 0.000 claims description 8
- 238000013507 mapping Methods 0.000 claims description 8
- 229920002223 polystyrene Polymers 0.000 claims description 8
- 238000002791 soaking Methods 0.000 claims description 8
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 claims description 7
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 claims description 6
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 6
- 244000005700 microbiome Species 0.000 claims description 6
- 230000035515 penetration Effects 0.000 claims description 6
- 239000004743 Polypropylene Substances 0.000 claims description 5
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 claims description 5
- 239000000203 mixture Substances 0.000 claims description 5
- 229920001155 polypropylene Polymers 0.000 claims description 5
- 206010021143 Hypoxia Diseases 0.000 claims description 4
- 239000004698 Polyethylene Substances 0.000 claims description 4
- 238000001035 drying Methods 0.000 claims description 4
- 230000000694 effects Effects 0.000 claims description 4
- 210000003527 eukaryotic cell Anatomy 0.000 claims description 4
- 230000001146 hypoxic effect Effects 0.000 claims description 4
- 229920000573 polyethylene Polymers 0.000 claims description 4
- 210000001236 prokaryotic cell Anatomy 0.000 claims description 4
- 239000000126 substance Substances 0.000 claims description 4
- POILWHVDKZOXJZ-ARJAWSKDSA-M (z)-4-oxopent-2-en-2-olate Chemical compound C\C([O-])=C\C(C)=O POILWHVDKZOXJZ-ARJAWSKDSA-M 0.000 claims description 3
- VFMUXPQZKOKPOF-UHFFFAOYSA-N 2,3,7,8,12,13,17,18-octaethyl-21,23-dihydroporphyrin platinum Chemical compound [Pt].CCc1c(CC)c2cc3[nH]c(cc4nc(cc5[nH]c(cc1n2)c(CC)c5CC)c(CC)c4CC)c(CC)c3CC VFMUXPQZKOKPOF-UHFFFAOYSA-N 0.000 claims description 3
- 230000004071 biological effect Effects 0.000 claims description 3
- 229920001577 copolymer Polymers 0.000 claims description 3
- 239000000835 fiber Substances 0.000 claims description 3
- GUCAYJHIKFEQFJ-DVACKJPTSA-M ir(cs)2(acac) Chemical compound N1C2=CC=CC=C2S[C]1C1=C([Ir](O\C(C)=C/C(C)=O)C=2C=3C=CC(=CC=3OC(=O)C=2[C]2SC3=CC=CC=C3N2)N(CC)CC)C2=CC=C(N(CC)CC)C=C2OC1=O GUCAYJHIKFEQFJ-DVACKJPTSA-M 0.000 claims description 3
- 239000012982 microporous membrane Substances 0.000 claims description 3
- NFHFRUOZVGFOOS-UHFFFAOYSA-N palladium;triphenylphosphane Chemical compound [Pd].C1=CC=CC=C1P(C=1C=CC=CC=1)C1=CC=CC=C1.C1=CC=CC=C1P(C=1C=CC=CC=1)C1=CC=CC=C1.C1=CC=CC=C1P(C=1C=CC=CC=1)C1=CC=CC=C1.C1=CC=CC=C1P(C=1C=CC=CC=1)C1=CC=CC=C1 NFHFRUOZVGFOOS-UHFFFAOYSA-N 0.000 claims description 3
- NAJUTOSXYIQTRT-UHFFFAOYSA-N platinum 5,10,15,20-tetrakis(2,3,4,5,6-pentafluorophenyl)-21,23-dihydroporphyrin Chemical compound [Pt].Fc1c(F)c(F)c(c(F)c1F)-c1c2ccc(n2)c(-c2c(F)c(F)c(F)c(F)c2F)c2ccc([nH]2)c(-c2c(F)c(F)c(F)c(F)c2F)c2ccc(n2)c(-c2c(F)c(F)c(F)c(F)c2F)c2ccc1[nH]2 NAJUTOSXYIQTRT-UHFFFAOYSA-N 0.000 claims description 3
- CTWKPPTYPMKFQL-UHFFFAOYSA-N platinum 5,10,15,20-tetraphenyl-21,23-dihydroporphyrin Chemical compound [Pt].c1cc2nc1c(-c1ccccc1)c1ccc([nH]1)c(-c1ccccc1)c1ccc(n1)c(-c1ccccc1)c1ccc([nH]1)c2-c1ccccc1 CTWKPPTYPMKFQL-UHFFFAOYSA-N 0.000 claims description 3
- 229920000515 polycarbonate Polymers 0.000 claims description 3
- 239000004417 polycarbonate Substances 0.000 claims description 3
- 229920002635 polyurethane Polymers 0.000 claims description 3
- 239000004814 polyurethane Substances 0.000 claims description 3
- 230000001464 adherent effect Effects 0.000 claims description 2
- PZXHLADRAIUBRZ-UHFFFAOYSA-N platinum 37,38,39,40-tetrazanonacyclo[28.6.1.13,10.112,19.121,28.04,9.013,18.022,27.031,36]tetraconta-1(37),2,4,6,8,10,12(39),13,15,17,19,21,23,25,27,29,31,33,35-nonadecaene Chemical compound [Pt].N1C(C=C2C3=CC=CC=C3C(C=C3C4=CC=CC=C4C(=C4)N3)=N2)=C(C=CC=C2)C2=C1C=C1C2=CC=CC=C2C4=N1 PZXHLADRAIUBRZ-UHFFFAOYSA-N 0.000 claims description 2
- 238000001556 precipitation Methods 0.000 claims description 2
- 230000004044 response Effects 0.000 claims description 2
- 125000000542 sulfonic acid group Chemical group 0.000 claims description 2
- 229910052723 transition metal Inorganic materials 0.000 claims description 2
- 150000003624 transition metals Chemical class 0.000 claims description 2
- 238000005406 washing Methods 0.000 claims description 2
- 239000012491 analyte Substances 0.000 description 87
- 239000000975 dye Substances 0.000 description 61
- 238000000691 measurement method Methods 0.000 description 5
- 230000010363 phase shift Effects 0.000 description 5
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 4
- 238000003556 assay Methods 0.000 description 4
- 238000000576 coating method Methods 0.000 description 4
- 239000011159 matrix material Substances 0.000 description 4
- 239000000758 substrate Substances 0.000 description 4
- 239000011149 active material Substances 0.000 description 3
- 239000011248 coating agent Substances 0.000 description 3
- 239000010408 film Substances 0.000 description 3
- 230000005283 ground state Effects 0.000 description 3
- 239000002904 solvent Substances 0.000 description 3
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 description 2
- 238000000149 argon plasma sintering Methods 0.000 description 2
- 230000004888 barrier function Effects 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 230000010261 cell growth Effects 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 238000011109 contamination Methods 0.000 description 2
- 230000001066 destructive effect Effects 0.000 description 2
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- 238000009501 film coating Methods 0.000 description 2
- 238000003384 imaging method Methods 0.000 description 2
- 230000000813 microbial effect Effects 0.000 description 2
- 229910052763 palladium Inorganic materials 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 238000011002 quantification Methods 0.000 description 2
- 238000010791 quenching Methods 0.000 description 2
- 230000000171 quenching effect Effects 0.000 description 2
- 230000000717 retained effect Effects 0.000 description 2
- 239000010409 thin film Substances 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- WCZXPQZPDFKPGH-UHFFFAOYSA-N 2-pyridin-2-ylpyridine;ruthenium(2+) Chemical group [Ru+2].N1=CC=CC=C1C1=CC=CC=N1 WCZXPQZPDFKPGH-UHFFFAOYSA-N 0.000 description 1
- 238000012604 3D cell culture Methods 0.000 description 1
- IAYPIBMASNFSPL-UHFFFAOYSA-N Ethylene oxide Chemical compound C1CO1 IAYPIBMASNFSPL-UHFFFAOYSA-N 0.000 description 1
- 239000012979 RPMI medium Substances 0.000 description 1
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 description 1
- JDUBRUYGFPDQNN-UHFFFAOYSA-N [Pt+2].FC1=C(C(=C(C(=C1C1=C2C=CC(C(=C3C=CC(=C(C=4C=CC(=C(C5=CC=C1N5)C5=C(C(=C(C(=C5F)F)F)F)F)N4)C4=C(C(=C(C(=C4F)F)F)F)F)N3)C3=C(C(=C(C(=C3F)F)F)F)F)=N2)F)F)F)F Chemical compound [Pt+2].FC1=C(C(=C(C(=C1C1=C2C=CC(C(=C3C=CC(=C(C=4C=CC(=C(C5=CC=C1N5)C5=C(C(=C(C(=C5F)F)F)F)F)N4)C4=C(C(=C(C(=C4F)F)F)F)F)N3)C3=C(C(=C(C(=C3F)F)F)F)F)=N2)F)F)F)F JDUBRUYGFPDQNN-UHFFFAOYSA-N 0.000 description 1
- IXPCJOPIVIEBBA-UHFFFAOYSA-N [Pt+2].N1C(C=C2N=C(C=C3NC(=C4)C=C3)C=C2)=CC=C1C=C1C=CC4=N1 Chemical compound [Pt+2].N1C(C=C2N=C(C=C3NC(=C4)C=C3)C=C2)=CC=C1C=C1C=CC4=N1 IXPCJOPIVIEBBA-UHFFFAOYSA-N 0.000 description 1
- 238000002835 absorbance Methods 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 239000011324 bead Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
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- 150000004035 chlorins Chemical class 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 239000007799 cork Substances 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000004043 dyeing Methods 0.000 description 1
- 210000002950 fibroblast Anatomy 0.000 description 1
- 238000000799 fluorescence microscopy Methods 0.000 description 1
- 238000012632 fluorescent imaging Methods 0.000 description 1
- 229920002313 fluoropolymer Polymers 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 238000005470 impregnation Methods 0.000 description 1
- MILUBEOXRNEUHS-UHFFFAOYSA-N iridium(3+) Chemical compound [Ir+3] MILUBEOXRNEUHS-UHFFFAOYSA-N 0.000 description 1
- 239000010410 layer Substances 0.000 description 1
- 238000002386 leaching Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000004020 luminiscence type Methods 0.000 description 1
- 210000004962 mammalian cell Anatomy 0.000 description 1
- 238000000386 microscopy Methods 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 239000004745 nonwoven fabric Substances 0.000 description 1
- MQZFZDIZKWNWFX-UHFFFAOYSA-N osmium(2+) Chemical compound [Os+2] MQZFZDIZKWNWFX-UHFFFAOYSA-N 0.000 description 1
- BSCHIACBONPEOB-UHFFFAOYSA-N oxolane;hydrate Chemical compound O.C1CCOC1 BSCHIACBONPEOB-UHFFFAOYSA-N 0.000 description 1
- 230000036284 oxygen consumption Effects 0.000 description 1
- 238000006213 oxygenation reaction Methods 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- UWCPBTNCCSZKGT-UHFFFAOYSA-N platinum 25,26,27,28-tetrazahexacyclo[16.6.1.13,6.18,11.113,16.019,24]octacosa-1(25),2,4,6,8(27),9,11,13,15,17,19,21,23-tridecaene Chemical compound [Pt].N1C(C=C2C3=CC=CC=C3C(C=C3NC(=C4)C=C3)=N2)=CC=C1C=C1C=CC4=N1 UWCPBTNCCSZKGT-UHFFFAOYSA-N 0.000 description 1
- 238000005381 potential energy Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- OVARTBFNCCXQKS-UHFFFAOYSA-N propan-2-one;hydrate Chemical compound O.CC(C)=O OVARTBFNCCXQKS-UHFFFAOYSA-N 0.000 description 1
- 230000003252 repetitive effect Effects 0.000 description 1
- 229910052707 ruthenium Inorganic materials 0.000 description 1
- 238000011012 sanitization Methods 0.000 description 1
- 239000002356 single layer Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000008223 sterile water Substances 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N31/00—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods
- G01N31/22—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods using chemical indicators
- G01N31/223—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods using chemical indicators for investigating presence of specific gases or aerosols
- G01N31/225—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods using chemical indicators for investigating presence of specific gases or aerosols for oxygen, e.g. including dissolved oxygen
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
- G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
- G01N21/64—Fluorescence; Phosphorescence
- G01N21/6428—Measuring fluorescence of fluorescent products of reactions or of fluorochrome labelled reactive substances, e.g. measuring quenching effects, using measuring "optrodes"
- G01N2021/6432—Quenching
Definitions
- Optically- active, target-analyte sensitive indicator dyes and compounded materials containing such dyes are widely used in the construction of materials and sensors for quantification and monitoring of target-analytes.
- Such sensors are particularly suited for use in those situations where non-invasive and/or continuous quantification and/or monitoring of a target-analyte within an enclosed space is necessary or desired as such sensors are amenable to repetitive, non-invasive and contactless interrogation through a variety of common barrier materials.
- Sensors employing an optically-active, target-analyte sensitive indicator dye commonly immobilize the dye by embedding the dye within a polymer matrix that is permeable to the target-analyte, hereinafter referenced as an optically- active indicator matrix.
- the optically- active indicator matrix is commonly deposited as a solid-state coating, film, layer or dot on an appropriate substrate support material to form autonomously deployable sensors. See for example United States Published Patent Applications 2011/0136247, 2009/0029402, 2008/199360, 2008/190172, 2007/0042412, and 2004/0033575; United States Patents 8,242,162, 8,158,438, 7,862,770, 7,849,729, 7,749,768, 7,679,745, 7,674,626, 7,569,395, 7,534,615, 7,368,153, 7,138,270, 6,989,246, 6,689,438, 6,395,506, 6,379,969, 6,080,574, 5,885,843, 5,863,460, 5,718,842, 5,595,708, 5,567,598, 5,462,879, 5,407,892, 5,114,676, 5,094,959, 5,030,420, 4,965,087, 4,
- a hydrophobic dye and a hydrophobic polymer in such sensors helps to improve sensor stability and reduce leaching of components to/from an aqueous test sample, while a microporous light- scattering substrate support material provides enhanced optical signals from the indicator material, mechanical strength, ease of fabrication and handling (e.g. Optech O2 sensors). While suitable for use in a wide variety of situations, conditions and environments, such composite solid state optical sensors are not always well suited for detection of target- analyte concentrations in an aqueous test-sample.
- sensors employing hydrophilic indicator materials tend to lose structural integrity and functional properties when immersed in the aqueous test sample, while sensors employing hydrophobic indicator materials (e.g., polystyrene) have reduced operational performance due to migration of indicator dye molecules into the substrate support material (i.e., formation of mixed polymer phases) during sensor fabrication and restricted contact between the hydrophobic sensor coating and the aqueous test sample (i.e., reduced wettability).
- hydrophobic indicator materials e.g., polystyrene
- US2007/243618 describes traditional oxygen sensors comprising a photolumine scent dye (Ru dye) dissolved in a fluorinated polymer and applied on a support as thin film coating. It does not have a 3D scaffolding structure and is made of a hydrophobic polymer and is impermeable to water. It is suitable for cell growth in 3D and oxygen imaging in 3D.
- WO2010/146361 describes an absorbance based indicator, which chemically reacts with oxygen to produce colour change. It is also prepared as thin film coating by applying polymer cocktail on support material. The sensor has no 3D scaffolding structure, and is not suitable for cell growth in 3D and oxygen imaging in 3D.
- the invention provides an oxygen sensitive material that is suitable for sensing oxygen in 3D spaces and in 3D cell cultures.
- the material comprises a microporous polymeric scaffolding formed from a polymer having a hydrophobic backbone and lateral hydrophilic side chains and side groups that make the scaffolding wettable.
- the material comprises a hydrophobic phosphorescent oxygen sensitive dye that is predominantly located in the hydrophobic backbone of the polymer.
- the microporous nature of the scaffold and the association of the dye with the polymer backbone provides a sensor material that is capable of sensing oxygen in 3D space.
- the microporous nature also allows cells to be grown in the material in a 3D space, and thereby allows oxygen consumption by the cells to be monitored in 3D, and not just as a monolayer of cells.
- the microporous nature of the scaffold also provides a light scattering effect that boosts light signals from the oxygen sensitive dye.
- the invention provides an oxygen sensitive material, comprising a microporous scaffolding selected from a microporous fibrous membrane or a microporous monolithic membrane impregnated with a phosphorescent oxygen sensitive dye, wherein:
- the microporous scaffolding is a polymer having a hydrophobic, oxygen permeable, polymer backbone with hydrophilic pendant groups or hydrophilic pendant chains that render the microporous scaffolding wettable, and
- the phosphorescent oxygen sensitive dye is a hydrophobic dye and typically is predominantly located in the hydrophobic polymer backbone.
- the oxygen sensitive material consists essentially of a microporous scaffolding selected from a microporous fibrous membrane or a microporous monolithic membrane impregnated with a phosphorescent oxygen sensitive dye, wherein:
- the microporous scaffolding is a polymer having a hydrophobic, oxygen permeable, polymer backbone with hydrophilic pendant groups or hydrophilic pendant chains that render the microporous scaffolding wettable, and
- the phosphorescent oxygen sensitive dye is a hydrophobic dye and typically is predominantly located in the hydrophobic polymer backbone.
- the membrane has an overall thickness of 20 to 3000 ⁇ .
- the microporous membrane has an average pore diameter of 2 to 500 ⁇ , and is ideally capable of acting as a scaffold for culturing adherent cells (i.e. eukaryotic or prokaryotic cells) in three-dimensional space.
- adherent cells i.e. eukaryotic or prokaryotic cells
- the microporous membrane is a non- woven, spun-bound, melt-bound or wet-laid membrane formed from fibers, typically having an average diameter of 1 to 50 ⁇ .
- the pores have an average wall thickness between pores of 5 to 200 ⁇ .
- the polymer backbone is selected from polyethylene, polypropylene and copolymers thereof.
- the microporous monolithic membrane has an average pore diameter of 10 to 500 ⁇ and, preferably, an average wall thickness between pores of 2 to 100 ⁇ .
- the polymer of the microporous monolithic membrane is selected from polystyrene, polyurethane, and polycarbonate.
- the scaffolding has hydrophilic pendant carboxylic acid chains.
- the pendant carboxylic acid chains are pendant acrylic acid chains.
- the polymer backbone is polystyrene and the scaffolding has pendant sulfonic acid groups.
- the phosphorescent oxygen sensitive dye has a responsive optical characteristic that changes in response to changes in the concentration or partial pressure of oxygen to which the sensor material is exposed.
- the responsive optical characteristic is at least one of photoluminescence lifetime, photoluminescence intensity and intensity ratio.
- the oxygen-sensitive phosphorescent dye is an oxygen sensitive photoluminescent transition metal complex selected from the group consisting of a platinum- tetrakis(pentafluorophenyl)porphyrin (PtPFPP), a palladium- tetrakis(pentafluorophenyl)porphyrin (PdPFPP), a platinum-octaethylporphyrin (PtOEP), a palladium-octaethylporphyrin (PdOEP), a platinum-octaethylporphyrinketone (PtOEPK), a palladium-octaethylporphyrinketone (PdOEPK), a platinum-tetraphenylporphyrin (PtTPP), a platinum-tetrabenzoporphyrin, a palladium-tetrabenzoporphyrin, a ruthenium- di
- the invention also provides a method of manufacturing an oxygen sensitive material according to the invention comprising the steps of:
- the microposous scaffolding is soaked with the solution for a duration sufficient to achieve at least 90 wt penetration of the solution into the microporous scaffolding relative to penetration achievable upon soaking for 24 hours, and (ii) the method further includes the step of washing the microporous scaffolding after depleting the organic solvent.
- the solution has a w/w ratio of water to organic solvent of between 20:80 and 80:20.
- the organic solvent is selected from the group consisting of tetrahydrofurane, dimethylformamide, ethanol and acetone.
- the organic solvent is evaporated in step (c) without any significant precipitation of the hydrophobic phosphorescent dye.
- the invention also provides a method for measuring oxygen concentration in an aqueous sample, comprising the steps of:
- the invention also provides a method for measuring concentration of oxygen within an enclosed space, comprising the steps of:
- the space is enclosed within a receptacle, and (ii) the probe is contactlessly interrogated through the receptacle.
- the invention also provides a method for monitoring changes in oxygen concentration in an aqueous test sample, comprising the steps of:
- step (iii) converting at least the identified emission measurements to an oxygen concentration based upon a known conversion algorithm, and (s) reporting at least one of (i) at least the two ascertained oxygen concentrations and the time interval between those reported concentrations, and (ii) a rate of change in oxygen concentration within the aqueous test sample calculated from data obtained in step (c).
- the invention also provides a method for monitoring changes in oxygen concentration within an enclosed space, comprising the steps of:
- step (x) reporting at least one of (i) at least the two ascertained oxygen concentrations and the time interval between those reported concentrations, and (ii) a rate of change in oxygen concentration within the enclosed space calculated from data obtained in step (d).
- the method is applied to achieve at least one of (i) a measurement of chemical activity of the test sample, (ii) a measurement of biological activity of the test sample, (iii) a presence/absence determination of a threshold concentration of aerobic microorganisms in the test sample, and (iv) an enumeration of aerobic microorganisms in the test sample at the time the test sample is placed in the space.
- the invention also provides a method for measuring and mapping differential oxygen concentrations within a cell culture, comprising the steps of:
- an image is generated that visually identifies those discrete areas within the cell support structure having an oxygen concentration below a threshold value indicative of hypoxic cells within the discrete area.
- the image is a 2-dimensional image.
- the image is a 3-dimensional image
- a first aspect of the invention is a dual-purpose target- analyte sensitive material capable of being effectively deployed as (i) a probe to measure target- analyte concentrations in both gaseous and aqueous environments, and (ii) cell culture scaffolding from which spatial distribution of oxygen concentration within the cell culture indicative of cell microenvironment can be measured and mapped.
- the material consists only of a porous wettable scaffolding impregnated with an optically-active, target- analyte sensitive dye in the absence of any other components that would materially affect functionality of the material as a probe and a cell microenvironment spatial distribution indicator.
- the material includes at least a porous wettable scaffolding impregnated with an optically-active, target- analyte sensitive dye.
- the porous scaffolding is a polymer having a hydrophobic polymer backbone with hydrophilic pendant groups or hydrophilic pendant chains
- the optically-active, target- analyte sensitive dye is a hydrophobic, photoluminescent, target- analyte sensitive dye.
- the porous scaffolding can be a microporous fibrous membrane or a microporous monolithic membrane, made of a suitable polymer such as polyethylene, polypropylene or polystyrene. It is preferably designed and constructed for culturing of eukaryotic or prokaryotic cells.
- a second aspect of the invention is a method of manufacturing a material according to the first aspect of the invention.
- the method includes the steps of (A) dissolving the hydrophobic, optically- active, target-analyte sensitive dye in a blend of water and a water- miscible organic solvent to form a solution, (B) soaking the scaffolding with the solution, (C) preferentially depleting the organic solvent from the solution in which the scaffolding is soaking, whereby the hydrophobic optically-active, target-analyte sensitive dye preferentially migrates to the hydrophobic backbone of the scaffolding, and (D) drying the scaffolding after depleting the organic solvent to form a wettable target-analyte sensitive material.
- a third aspect of the invention is a method for measuring concentration of a target-analyte in an aqueous sample employing a probe constructed from material according to the first aspect of the invention.
- the method includes the steps of (A) obtaining a probe constructed from the target-analyte sensitive material according to the first aspect of the invention, (B) placing the probe into direct fluid communication with an aqueous test sample whereby the sample wets the probe, and (C) ascertaining target-analyte concentration within the aqueous test sample by: (i) exposing the probe to excitation radiation to create an excited probe, (ii) measuring radiation emitted by the excited probe, and (iii) converting the measured emission to a target-analyte concentration based upon a known conversion algorithm.
- a fourth aspect of the invention is a method for measuring concentration of a target-analyte within an enclosed space employing a probe constructed from material according to the first aspect of the invention.
- the method includes the steps of (A) obtaining a probe constructed from the target-analyte sensitive material according to the first aspect of the invention, (B) placing the probe within a space, (C) enclosing the space, and (D) ascertaining target-analyte concentration within the enclosed space by: (i) exposing the probe to excitation radiation to create an excited probe, (ii) measuring radiation emitted by the excited probe, and (iii) converting the measured emission to a target-analyte concentration based upon a known conversion algorithm.
- a fifth aspect of the invention is a method for monitoring changes in target- analyte concentration in an aqueous test sample employing a probe constructed from material according to the first aspect of the invention.
- the method includes the steps of (A) obtaining a probe constructed from the target- analyte sensitive material according to the first aspect of the invention, (B) placing the probe into direct fluid communication with an aqueous test sample whereby the sample wets the probe, (C) ascertaining target- analyte concentration within the aqueous test sample over time by: (i) taking at least two emission measurements over time, each measurement comprising the steps of: (1) exposing the probe to excitation radiation to create an excited probe, and (2) measuring radiation emitted by the excited probe, (ii) measuring passage of time between at least two of the emission measurements to determine a time interval between identified emission measurements, and (iii) converting at least the identified emission measurements to a target-analyte concentration based upon a known conversion algorithm, and (E) reporting at least one
- a sixth aspect of the invention is a method for monitoring changes in target-analyte concentration within an enclosed space employing a probe constructed from material according to the first aspect of the invention.
- the method includes the steps of (A) obtaining a probe constructed from the target-analyte sensitive material according to the first aspect of the invention, (B) placing the probe within a space, (C) enclosing the space, (D) ascertaining target-analyte concentration within the enclosed space over time by: (i) taking at least two emission measurements over time, each measurement comprising the steps of: (1) exposing the probe to excitation radiation to create an excited probe, and (2) measuring radiation emitted by the excited probe, (ii) measuring passage of time between at least two of the emission measurements to determine a time interval between identified emission measurements, and (iii) converting at least the identified emission measurements to a target- analyte concentration based upon a known conversion algorithm, and (E) reporting at least one of (i) at least the two ascertained target-an
- a seventh aspect of the invention is a method for measuring and mapping differential oxygen concentrations within a cell culture employing a cell support structure constructed from material according to the first aspect of the invention.
- the method includes the steps of (A) obtaining a cell support structure constructed from the target- analyte sensitive material according to the first aspect of the invention wherein the target- analyte is oxygen, (B) culturing cells within the cell support structure, and (C) ascertaining local oxygen concentrations within the cell support structure by: (i) exposing a discrete area of the cell support structure to excitation radiation to create an excited area on the structure, (ii) measuring radiation emitted by the excited discrete area, (iii) determining oxygen concentration within the excited discrete area, and (iv) optionally generating an image mapping the determined spatial distribution of oxygen over the cell support structure.
- the phrase "permeable" means a material that when formed into a 1 mil film has a target- analyte transmission rate of greater than 100 c 3 /m 2 day when measured in accordance with ASTM D 3985 when the target analyte is oxygen and when measured in accordance with ASTM D 1434 when the target analyte is other than oxygen.
- the phrase "highly permeable” means a material that when formed into a 1 mil film has a target- analyte transmission rate of greater than 1,000 c 3 /m 2 day when measured in accordance with ASTM D 3985 when the target analyte is oxygen and when measured in accordance with ASTM D 1434 when the target analyte is other than oxygen.
- target-analyte refers to a gaseous chemical substance, typically O2, NH3 or CO2, capable of proportionally altering an optical property of an optically-active material containing a photoluminescent dye.
- contactless interrogation means interrogation without tangible physical contact with the interrogated device, whereby interrogation can occur through an intervening physical barrier.
- the term “interrogation light” means electromagnetic radiation having a wavelength between 400 and 1000 nm, encompassing both excitation and emission light.
- the term “wettable” means the ability of a water droplet to penetrate into the pores of a porous substrate as opposed to forming a bead at or proximate to the surface interface, effective for providing direct fluid communication between the water and the walls of the pores.
- Luminescence encompasses both fluorescence and phosphorescence. Electromagnetic radiation in the ultraviolet or visible region is used to excite molecules to higher electronic energy levels. The excited molecules lose their excess energy by one of several methods. One of those methods is fluorescence. Fluorescence refers to the radiative transition of electrons from the first excited singlet state to the singlet ground state (Si .to So). The lifetime of fluorescence is relatively short, approximately 10 "9 to 10 "7 seconds.
- the triplet state so produced may return to the ground state by a radiative process known as phosphorescence.
- Phosphorescence is the radiative relaxation of an electron from the lowest excited triplet state to the singlet ground state (Ti to So). Because the transition that leads to phosphorescence involves a change in spin multiplicity, it has a low probability and hence a relatively long lifetime of 10 "4 to 10 seconds. Fluorescent and phosphorescent intensity and lifetime are known to change in a defined fashion relative to changes in the partial pressure of a target- analyte capable of quenching the photolumine scent molecules. Hence, the partial pressure of a target-analyte in fluid communication with a photolumine scent dye can be determined by measuring photoluminescence intensity, intensity ratio and/or lifetime.
- a first aspect of the invention is a dual-purpose target-analyte sensitive material capable of being effectively deployed as (i) a probe to measure target-analyte concentrations in both gaseous and aqueous environments, and (ii) cell culture scaffolding from which spatial distribution of oxygen concentration within the cell culture indicative of cell microenvironment can be measured and mapped.
- the material is capable of reporting the partial pressure, and thereby the concentration, of a target- analyte (PA).
- PA target- analyte
- the materials are preferably in the form of a membrane although other structures are possible.
- the materials are remotely interrogatable by optical means and autonomously positionable, thereby permitting the materials to be used for a wide variety of purposes.
- the material When employed as a probe, the material is suitable for use in combination with a wide variety of assay vessels to quickly, easily and reliably measure and monitor changes in analyte concentration in an environment.
- the materials are particularly well suited for use as a probe to measure and monitor changes in target-analyte concentration in an enclosed environment in a non-invasive and non-destructive manner.
- the material When employed as cell culture scaffolding, the material is suitable for use in combination with a wide variety of culturing vessels to quickly, easily and reliably measure and monitor localized changes in oxygen concentration throughout the scaffolding, from which spatial distribution of oxygen concentration within the cell culture indicative of cell microenvironment can be measured and mapped in a non-invasive and non-destructive manner.
- the materials are sensitive to a target-analyte, such as O2, CO2, or CO.
- a target-analyte such as O2, CO2, or CO.
- O2 the target-analyte since C -sensitive materials are the most commonly used types of optically active materials.
- the material is comprises of a porous wettable scaffolding impregnated with an optically- active, oxygen sensitive dye.
- the porous scaffolding is a polymer having a hydrophobic polymer backbone with hydrophilic pendant groups or hydrophilic pendant chains.
- the polymer should be (i) structurally stable, (ii) compatible with the solvent based oxygen sensitive coating solution during the coating process, (iii) compatible with the dry dye, (iv) inert when used in accordance with its intended use, and (v) oxygen permeable.
- the size and density of hydrophilic pendant chains on the hydrophobic polymer backbone should be sufficient to render the scaffolding readily wettable throughout such that an aqueous test sample, including cells suspended in a cell culture medium, may promptly penetrate into the pores and into intimate sensing contact with the dye.
- the material when employed as a membrane, preferably has an overall thickness of 20 to 3000 ⁇ .
- the scaffolding may be a non-woven, spun-bound, melt-bound or wet-laid membrane, preferrably formed from fibers having an average diameter of 1 to 50 ⁇ .
- the non-woven scaffolding preferably has an average pore diameter of 2 to 500 ⁇ and an average wall thickness between pores of 5 to 200 ⁇ .
- suitable materials for use as the porous nonwoven scaffolding includes specifically, but not exclusively backbones of polyethylene, polypropylene and copolymers thereof, with grafted hydrophilic pendant groups or side chains such as a carboxylic acid chain.
- a preferred carboxylic acid for use as the side chain is acrylic acid.
- Suitable nonwoven scaffolding is available from a number of sources including Freudenberg Nonwovens LP.
- the scaffolding may be a monolithic microporous polymeric material, preferably having an average pore diameter of 10 to 500 ⁇ and an average wall thickness between pores of 2 to 100 ⁇ .
- suitable materials for use as the porous monolithic scaffolding includes specifically, but not exclusively backbones of polystyrene, polyurethane, and polycarbonate, with grafted hydrophilic pendant groups or side chains such as a carboxylic acid chain.
- a preferred carboxylic acid for use as the side chain is acrylic acid.
- the scaffolding is impregnated with a hydrophobic, photoluminescent, oxygen sensitive dye. Contrary to customary practice, the dye is preferably impregnated sans any "embedding" polymer matrix in the dye solution.
- Preferred photoluminescent indicator dyes are long-decay fluorescent or phosphorescent indicator dyes.
- a nonexhaustive list of suitable P02 sensitive photoluminescent dyes includes specifically, but not exclusively, ruthenium(II)-bipyridyl and ruthenium(II)- diphenylphenanothroline complexes, porphyrin-ketones such as platinum(II)- octaethylporphine-ketone, platinum(II)-porphyrin such as platinum(II)- tetrakis(pentafluorophenyl)porphine, palladium(II)-porphyrin such as palladium(II)- tetrakis(pentafluorophenyl)porphine, phosphorescent metallocomplexes of tetrabenzoporphyrins,
- Preferred P02 sensitive photoluminescent dyes include platinum- tetrakis(pentafluorophenyl)porphyrin (PtPFPP), palladium- tetrakis(pentafluorophenyl)porphyrin (PdPFPP), platinum-octaethylporphyrin (PtOEP), palladium-octaethylporphyrin (PdOEP), platinum-octaethylporphyrinketone (PtOEPK), palladium-octaethylporphyrinketone (PdOEPK), platinum-tetraphenylporphyrin (PtTPP), platinum-benzoporphyrin, palladium-benzoporphyrin, ruthenium-diphenylphenanotroline bis(hexafluorophosphate) (Ru(dpp) 3 ), and iridium-bis-3-(l,3-benzo
- the oxygen- sensitive photoluminescent dye may be compounded with another dye sensitive to a different target-analyte, a target-analyte insensitive reference dye or other additives known to those of skill in the art.
- the optically active material can be manufactured by any suitable technique.
- One technique is to (i) dissolve the dye in a suitable blend of water and a water-miscible organic solvent such as tetrahydrofurane, dimethylformamide or acetone, to form a solution, (ii) immersing and incubating the porous scaffolding in the solution, (iii) preferentially depleting the organic solvent from the solution, such as by heating to a temperature that favors evaporation of the organic solvent over water, whereby the dye preferentially migrates to the hydrophobic backbone of the scaffolding, and (iv) drying the scaffolding.
- the scaffolding may be washed and dried one or more times after the initial dyeing.
- the solution may be sprayed or spotted onto the scaffolding.
- the w/w ratio of water to organic solvent in the solution is preferably between 20:80 and 80:20.
- the concentration of dye in the solvent blend should be in the range of 0.01 to 5% w/w.
- the scaffolding is preferably immersed in the solution for a duration sufficient to achieve at least 90 wt% penetration of the solution into the scaffolding relative the level of penetration achieved upon immersion for 24 hours, without dissolving or changing the structure of the scaffolding material.
- the material may be sanitized or sterilized before or after packaging by any suitable means, such as heat, gamma irradiation or ethylene oxide, on order to avoid microbial contamination of a sample undergoing microbial testing with the material.
- the material can be used as a probe to quickly, easily, accurately and reliably measure the concentration of a target- analyte in an aqueous test sample ⁇ e.g., oxygen in waste water).
- the probe can be interrogated in the same manner as typical target- analyte sensitive photolumine scent materials are interrogated.
- the material can be used to measure the concentration of a target- analyte in an aqueous test sample by (A) placing the probe into direct fluid communication with the aqueous test sample whereby the sample wets the probe, at a location where radiation at the excitation and emission wavelengths of the dye can be transmitted to and received from the material with minimal interference by the vessel in which the test sample is retained or the test sample itself, (B) interrogating the material with an interrogation device, and (C) converting the measured emissions to a target- analyte concentration within the aqueous test sample based upon a known conversion algorithm or look-up table. Conversion algorithms used to convert the measured emissions to a target- analyte concentration are well know to and readily developable by those with routine skill in the art.
- Interrogation of the probe involves exposing the probe to excitation radiation to create an excited probe and, (ii) measuring radiation emitted by the excited probe from which analyte concentration of a test sample in fluid communication with the probe can be ascertained.
- the radiation emitted by the excited material 10 can be measured in terms of photoluminescence intensity, intensity ratio and/or lifetime (rate of decay, phase shift or anisotropy), with measurement of lifetime generally preferred as a more accurate and reliable measurement technique when seeking to establish the extent to which the dye has been quenched by target- analyte.
- the material can be used as a probe to quickly, easily, accurately and reliably measure the concentration of a target- analyte in an environment ⁇ e.g., the sealed chamber 59 of an assay vessel 50 or the sealed chamber of a package containing a product susceptible to spoilage or deterioration).
- the probe can be interrogated in the same manner as typical target- analyte sensitive photoluminescent materials are interrogated.
- the material is used to measure the concentration of a target- analyte in an environment by (A) placing the probe into fluid communication with the environment to be monitored ⁇ e.g., within the sealed chamber of an assay vessel containing a test sample) at a location where radiation at the excitation and emission wavelengths of the dye can be transmitted to and received from the probe with minimal interference and without opening or otherwise breaching the integrity of the environment (e.g., without opening the assay vessel), (B) interrogating the probe with an interrogation device, and (C) converting the measured emissions to a target- analyte concentration within the environment based upon a known conversion algorithm or look-up table. Conversion algorithms used to convert the measured emissions to a target- analyte concentration are well know to and readily developable by those with routine skill in the art.
- Interrogation of the probe involves exposing the probe to excitation radiation to create an excited probe and, (ii) measuring radiation emitted by the excited probe.
- the radiation emitted by the probe can be measured in terms of photoluminescence intensity, intensity ratio and/or lifetime (rate of decay, phase shift or anisotropy), with measurement of lifetime generally preferred as a more accurate and reliable measurement technique when seeking to establish the extent to which the dye has been quenched by target- analyte.
- the material can be used as a probe to quickly, easily, accurately and reliably measure changes in target- analyte concentration in an aqueous test sample by (i) placing the probe into direct fluid communication with the aqueous test sample whereby the sample wets the probe, at a location where radiation at the excitation and emission wavelengths of the dye can be transmitted to and received from the material with minimal interference by the vessel in which the test sample is retained or the test sample itself, (B) ascertaining target- analyte concentration within the aqueous test sample over time by (i) repeatedly exposing the probe to excitation radiation over time, (ii) measuring radiation emitted by the excited probe after at least some of the exposures, (iii) measuring passage of time during the repeated excitation exposures and emission measurements, and (iv) converting at least some of the measured emissions to a target-analyte concentration based upon a known conversion algorithm or look-up table, and (C) reporting at least one of (i) at least two ascertained target-ana
- Conversion algorithms used to convert the measured emissions to a target-analyte concentration are well know to and readily developable by those with routine skill in the art.
- the radiation emitted by the probe can be measured in terms of photoluminescence intensity, intensity ratio and/or lifetime (rate of decay, phase shift or anisotropy), with measurement of lifetime generally preferred as a more accurate and reliable measurement technique when seeking to establish the extent to which the dye has been quenched by target- analyte.
- the material can be used as a probe to quickly, easily, accurately and reliably measure changes in target- analyte concentration in an enclosed environment by (i) placing the probe into fluid communication with the environment to be monitored at a location where radiation at the excitation and emission wavelengths of the dye can be transmitted to and received from the probe with minimal interference by the vessel enclosing the environment or the environment itself, and without physically accessing or otherwise breaching the integrity of the environment, (B) ascertaining target- analyte concentration within the environment over time by (i) repeatedly exposing the probe to excitation radiation over time, (ii) measuring radiation emitted by the excited probe after at least some of the exposures, (iii) measuring passage of time during the repeated excitation exposures and emission measurements, and (iv) converting at least some of the measured emissions to a target- analyte concentration based upon a known conversion algorithm or look-up table, and (C) reporting at least one of (i) at least two ascertained target- analyte concentrations and the time
- the radiation emitted by the probe can be measured in terms of photoluminescence intensity, intensity ratio and/or lifetime (rate of decay, phase shift or anisotropy), with measurement of lifetime generally preferred as a more accurate and reliable measurement technique when seeking to establish the extent to which the dye has been quenched by target- analyte.
- Use of the probe to measure changes in target- analyte concentration in an enclosed environment is particularly well suited for use in a number of applications, including specifically but not exclusively (i) measurement of chemical activity of a test sample, (ii) measurement of biological activity of a test sample, (iii) presence/absence determination of a threshold concentration of aerobic microorganisms in a test sample, and (iv) enumeration of aerobic microorganisms in a test sample as of the time the test sample is placed in the enclosed space.
- the material can be used as a support scaffolding for the culturing of cells, from which the spatial distribution of differences in cell microenvironment throughout the culture can be ascertained and mapped.
- the method includes the steps of (i) culturing cells (e.g., eukaryotic or prokaryotic cells) within a cell support structure comprising the material, (ii) interrogating the support scaffolding with an interrogation device capable of measuring spatial distribution of radiation emitted by the excited structure, and (iii) generating an image mapping the measured spatial distribution of radiation.
- Interrogation of the support scaffolding involves exposing the support scaffolding to excitation radiation to create an excited support scaffolding and, (ii) detecting and measuring or visually depicting difference in localized radiation emitted by the excited probe.
- Fluorescence microscopy including wide-field, laser scanning and two-photon microscopy devices, are suitable for interrogating the support scaffolding and generating an image depicting spatial distribution of radiation emitted by the excited structure.
- Other devices may also be employed.
- the device preferably generates an image, either a two-dimensional image or a three-dimensional image, indicating at least those areas having an oxygen concentration below a threshold value indicative of hypoxic cells within the area.
- the radiation emitted by the excited support scaffolding can be measured in terms of photoluminescence intensity, intensity ratio and/or lifetime (rate of decay, phase shift or anisotropy), with measurement of lifetime generally preferred as a more accurate and reliable measurement technique when seeking to establish the extent to which the dye has been quenched by oxygen, correlating to the extent to which oxygen has been depleted by the presence of viable cells proximate the area.
- a 15 x 30 mm sheet of spun-bound polypropylene grafted with acrylic chains is soaked in 10 mL of a tetrahydrofuran- water (70:30 % w/w) solution containing 0.02 mg/ml PtPFPP dye in a capped vessel for lh at 60°C.
- the contents of the vessel were then placed under moderate vacuum (50 mmHg) on a rotary evaporator to gradually and preferentially evaporate the THF ( ⁇ lh at 40°C).
- the material was subsequently dried in an oven at 70°C for 16 hours and then processed into individual 02 sensitive probes suitable for use in detecting 02 concentrations in both gaseous and aqueous liquid samples.
- Disks of hydrophylic microporous polystyrene scaffolds (15 mm in diameter, Reinnervate) are placed in the wells of 12-well plates (Sarstedt), covered with 2 mL of an acetone-water (70:30 % w/w) solution containing 0.05 mg/ml PtPFPP dye and incubated for 2 hours at 60°C to evaporate organic solvent.
- the incubated scaffolds were quickly rinsed with 50% ethanol, then with sterile water and dried to form phosphorescent O2 sensitive scaffolds.
- These phosphorescent O2 sensitive scaffolds are used to culture mammalian cells (mouse embryonic fibroblasts in RPMI medium) and monitor oxygenation of cells in different parts of the scaffold by live cell fluorescent imaging. Regions of the scaffold with cells producing high optical signals (phosphorescence lifetime or intensity) correspond to hypoxic zones.
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Abstract
An oxygen sensitive material capable of deployment as both a probe to measure oxygen concentrations in both gaseous and aqueous environments, and as a cell culture scaffolding from which spatial distribution of oxygen concentration within the cell culture can be measured and mapped, is provided The material is a microporous wettable scaffolding impregnated with a hydrophobic phosphorescent oxygen sensitive dye wherein the scaffolding is a polymer having a hydrophobic polymer backbone with hydrophilic pendant groups and/or hydrophilic pendant chains.
Description
AN OXYGEN SENSITIVE MATERIAL, AND USE THEREOF TO SENSE OXYGEN
IN THREE-DIMENSIONAL SPACES
BACKGROUND
Optically- active, target-analyte sensitive indicator dyes and compounded materials containing such dyes are widely used in the construction of materials and sensors for quantification and monitoring of target-analytes. Such sensors are particularly suited for use in those situations where non-invasive and/or continuous quantification and/or monitoring of a target-analyte within an enclosed space is necessary or desired as such sensors are amenable to repetitive, non-invasive and contactless interrogation through a variety of common barrier materials.
Sensors employing an optically-active, target-analyte sensitive indicator dye commonly immobilize the dye by embedding the dye within a polymer matrix that is permeable to the target-analyte, hereinafter referenced as an optically- active indicator matrix.
To facilitate handling and use, and avoid contamination of the sample being tested, the optically- active indicator matrix is commonly deposited as a solid-state coating, film, layer or dot on an appropriate substrate support material to form autonomously deployable sensors. See for example United States Published Patent Applications 2011/0136247, 2009/0029402, 2008/199360, 2008/190172, 2007/0042412, and 2004/0033575; United States Patents 8,242,162, 8,158,438, 7,862,770, 7,849,729, 7,749,768, 7,679,745, 7,674,626, 7,569,395, 7,534,615, 7,368,153, 7,138,270, 6,989,246, 6,689,438, 6,395,506, 6,379,969, 6,080,574, 5,885,843, 5,863,460, 5,718,842, 5,595,708, 5,567,598, 5,462,879, 5,407,892, 5,114,676, 5,094,959, 5,030,420, 4,965,087, 4,810,655, and 4,476,870; PCT International Published Application WO 2008/146087; and European Published Patent Application EP 1134583. Such optical sensors are available from a number of suppliers, including Presens GmbH of Regensburg, Germany, Oxysense of Dallas, Texas, USA, and Luxcel Biosciences, Ltd of Cork, Ireland.
The use of a hydrophobic dye and a hydrophobic polymer in such sensors helps to improve sensor stability and reduce leaching of components to/from an aqueous test sample, while a microporous light- scattering substrate support material provides enhanced optical signals from the indicator material, mechanical strength, ease of fabrication and handling (e.g. Optech O2 sensors). While suitable for use in a wide variety of situations, conditions and environments, such composite solid state optical sensors are not always well suited for
detection of target- analyte concentrations in an aqueous test-sample. Sensors employing hydrophilic indicator materials tend to lose structural integrity and functional properties when immersed in the aqueous test sample, while sensors employing hydrophobic indicator materials (e.g., polystyrene) have reduced operational performance due to migration of indicator dye molecules into the substrate support material (i.e., formation of mixed polymer phases) during sensor fabrication and restricted contact between the hydrophobic sensor coating and the aqueous test sample (i.e., reduced wettability).
US2007/243618 describes traditional oxygen sensors comprising a photolumine scent dye (Ru dye) dissolved in a fluorinated polymer and applied on a support as thin film coating. It does not have a 3D scaffolding structure and is made of a hydrophobic polymer and is impermeable to water. It is suitable for cell growth in 3D and oxygen imaging in 3D. WO2010/146361 describes an absorbance based indicator, which chemically reacts with oxygen to produce colour change. It is also prepared as thin film coating by applying polymer cocktail on support material. The sensor has no 3D scaffolding structure, and is not suitable for cell growth in 3D and oxygen imaging in 3D.
It is an object of the invention to overcome at least one of the above-referenced problems.
STATEMENTS OF INVENTION
Broadly, the invention provides an oxygen sensitive material that is suitable for sensing oxygen in 3D spaces and in 3D cell cultures. The material comprises a microporous polymeric scaffolding formed from a polymer having a hydrophobic backbone and lateral hydrophilic side chains and side groups that make the scaffolding wettable. The material comprises a hydrophobic phosphorescent oxygen sensitive dye that is predominantly located in the hydrophobic backbone of the polymer. The microporous nature of the scaffold and the association of the dye with the polymer backbone provides a sensor material that is capable of sensing oxygen in 3D space. The microporous nature also allows cells to be grown in the material in a 3D space, and thereby allows oxygen consumption by the cells to be monitored in 3D, and not just as a monolayer of cells. The microporous nature of the scaffold also provides a light scattering effect that boosts light signals from the oxygen sensitive dye.
In a first aspect, the invention provides an oxygen sensitive material, comprising a microporous scaffolding selected from a microporous fibrous membrane or a microporous monolithic membrane impregnated with a phosphorescent oxygen sensitive dye, wherein:
(a) the microporous scaffolding is a polymer having a hydrophobic, oxygen permeable, polymer backbone with hydrophilic pendant groups or hydrophilic pendant chains that render the microporous scaffolding wettable, and
(b) the phosphorescent oxygen sensitive dye is a hydrophobic dye and typically is predominantly located in the hydrophobic polymer backbone.
Typically, the oxygen sensitive material, consists essentially of a microporous scaffolding selected from a microporous fibrous membrane or a microporous monolithic membrane impregnated with a phosphorescent oxygen sensitive dye, wherein:
(c) the microporous scaffolding is a polymer having a hydrophobic, oxygen permeable, polymer backbone with hydrophilic pendant groups or hydrophilic pendant chains that render the microporous scaffolding wettable, and
(d) the phosphorescent oxygen sensitive dye is a hydrophobic dye and typically is predominantly located in the hydrophobic polymer backbone.
Suitably, the membrane has an overall thickness of 20 to 3000 μιη.
Typically, the microporous membrane has an average pore diameter of 2 to 500 μιη, and is ideally capable of acting as a scaffold for culturing adherent cells (i.e. eukaryotic or prokaryotic cells) in three-dimensional space.
In one embodiment, the microporous membrane is a non- woven, spun-bound, melt-bound or wet-laid membrane formed from fibers, typically having an average diameter of 1 to 50 μιη.
Typically, the pores have an average wall thickness between pores of 5 to 200 μιη. Ideally, the polymer backbone is selected from polyethylene, polypropylene and copolymers thereof.
In another embodiment, the microporous monolithic membrane has an average pore diameter of 10 to 500 μιη and, preferably, an average wall thickness between pores of 2 to 100 μιη.
Suitably, the polymer of the microporous monolithic membrane is selected from polystyrene, polyurethane, and polycarbonate.
Preferably, the scaffolding has hydrophilic pendant carboxylic acid chains. Typically, the pendant carboxylic acid chains are pendant acrylic acid chains.
In one embodiment, the polymer backbone is polystyrene and the scaffolding has pendant sulfonic acid groups.
Preferably, the phosphorescent oxygen sensitive dye has a responsive optical characteristic that changes in response to changes in the concentration or partial pressure of oxygen to which the sensor material is exposed.
Suitably, the responsive optical characteristic is at least one of photoluminescence lifetime, photoluminescence intensity and intensity ratio.
Typically, the oxygen-sensitive phosphorescent dye is an oxygen sensitive photoluminescent transition metal complex selected from the group consisting of a platinum- tetrakis(pentafluorophenyl)porphyrin (PtPFPP), a palladium- tetrakis(pentafluorophenyl)porphyrin (PdPFPP), a platinum-octaethylporphyrin (PtOEP), a palladium-octaethylporphyrin (PdOEP), a platinum-octaethylporphyrinketone (PtOEPK), a palladium-octaethylporphyrinketone (PdOEPK), a platinum-tetraphenylporphyrin (PtTPP), a platinum-tetrabenzoporphyrin, a palladium-tetrabenzoporphyrin, a ruthenium- diphenylphenanotroline bis(hexafluorophosphate) (Ru(dpp)3), and an iridium-bis-3-(l,3- benzothiazol-2-yl)-7-(diethylamino)-2H-chromen-2-one acetylacetonate (Ir(Cs)2(acac)).
The invention also provides a method of manufacturing an oxygen sensitive material according to the invention comprising the steps of:
(e) dissolving the hydrophobic, oxygen sensitive phosphorescent dye in a blend of water and a water-miscible organic solvent to form a solution,
(f) soaking the microporous scaffolding with the solution,
(g) preferentially depleting the organic solvent from the solution in which the scaffolding is soaking, whereby the hydrophobic oxygen sensitive
phosphorescent dye preferentially migrates to the hydrophobic backbone of the scaffolding, and
(h) drying the microporous scaffolding after depleting the organic solvent to form a wettable oxygen sensitive material.
Preferably, (i) the microposous scaffolding is soaked with the solution for a duration sufficient to achieve at least 90 wt penetration of the solution into the microporous scaffolding relative to penetration achievable upon soaking for 24 hours, and (ii) the method further includes the step of washing the microporous scaffolding after depleting the organic solvent.
Preferably, the solution has a w/w ratio of water to organic solvent of between 20:80 and 80:20.
Typically, the organic solvent is selected from the group consisting of tetrahydrofurane, dimethylformamide, ethanol and acetone.
Suitably, at least 90% of the organic solvent is dissipated in step (c).
Typically, the organic solvent is evaporated in step (c) without any significant precipitation of the hydrophobic phosphorescent dye.
The invention also provides a method for measuring oxygen concentration in an aqueous sample, comprising the steps of:
(i) obtaining a probe constructed from the oxygen sensitive material of the invention,
(j) placing the probe into direct fluid communication with an aqueous test sample whereby the sample wets the probe, and
(k) ascertaining oxygen concentration within the aqueous test sample by:
(i) exposing the probe to excitation radiation to create an excited probe,
(ii) measuring radiation emitted by the excited probe, and
(iii) converting the measured emission to an oxygen concentration based upon a known conversion algorithm.
The invention also provides a method for measuring concentration of oxygen within an enclosed space, comprising the steps of:
(1) obtaining a probe constructed from the oxygen sensitive material of the invention
(m) placing the probe within a space,
(n) enclosing the space, and
(o) ascertaining oxygen concentration within the enclosed space by:
(i) exposing the probe to excitation radiation to create an excited probe,
(ii) measuring radiation emitted by the excited probe, and
(iii) converting the measured emission to an oxygen concentration based upon a known conversion algorithm.
Preferably, (i) the space is enclosed within a receptacle, and (ii) the probe is contactlessly interrogated through the receptacle.
The invention also provides a method for monitoring changes in oxygen concentration in an aqueous test sample, comprising the steps of:
(p) obtaining a probe constructed from the oxygen sensitive material of the invention,
(q) placing the probe into direct fluid communication with an aqueous test sample whereby the sample wets the probe,
(r) ascertaining oxygen concentration within the aqueous test sample over time by:
(i) taking at least two emission measurements over time, each measurement comprising the steps of:
(1) exposing the probe to excitation radiation to create an excited probe, and
(2) measuring radiation emitted by the excited probe,
(ii) measuring passage of time between at least two of the emission measurements to determine a time interval between identified emission measurements, and
(iii) converting at least the identified emission measurements to an oxygen concentration based upon a known conversion algorithm, and
(s) reporting at least one of (i) at least the two ascertained oxygen concentrations and the time interval between those reported concentrations, and (ii) a rate of change in oxygen concentration within the aqueous test sample calculated from data obtained in step (c).
The invention also provides a method for monitoring changes in oxygen concentration within an enclosed space, comprising the steps of:
(t) obtaining a probe constructed from the oxygen sensitive material of the invention,
(u) placing the probe within a space,
(v) enclosing the space,
(w) ascertaining oxygen concentration within the enclosed space over time by:
(i) taking at least two emission measurements over time, each measurement comprising the steps of:
(1) exposing the probe to excitation radiation to create an excited probe, and
(2) measuring radiation emitted by the excited probe,
(ii) measuring passage of time between at least two of the emission measurements to determine a time interval between identified emission measurements, and
(iii) converting at least the identified emission measurements to an oxygen concentration based upon a known conversion algorithm, and
(x) reporting at least one of (i) at least the two ascertained oxygen concentrations and the time interval between those reported concentrations, and (ii) a rate of change in oxygen concentration within the enclosed space calculated from data obtained in step (d).
Preferably, the method is applied to achieve at least one of (i) a measurement of chemical activity of the test sample, (ii) a measurement of biological activity of the test sample, (iii) a presence/absence determination of a threshold concentration of aerobic microorganisms in the test sample, and (iv) an enumeration of aerobic microorganisms in the test sample at the time the test sample is placed in the space.
The invention also provides a method for measuring and mapping differential oxygen concentrations within a cell culture, comprising the steps of:
(y) obtaining a cell support structure constructed from the oxygen sensitive material of the invention
(z) culturing cells within the cell support structure, and
(aa) ascertaining local oxygen concentrations within the cell support structure by:
(i) exposing a discrete area within the cell support structure to excitation radiation to create an excited area on the structure,
(ii) measuring radiation emitted by the excited discrete area,
(iii) determining oxygen concentration within the excited discrete area, and
(iv) optionally generating an image mapping the determined spatial distribution of oxygen over the cell support structure.
Preferably, an image is generated that visually identifies those discrete areas within the cell support structure having an oxygen concentration below a threshold value indicative of hypoxic cells within the discrete area.
Suitably, the image is a 2-dimensional image. Alternatively, the image is a 3-dimensional image
DETAILED DESCRIPTION OF THE INVENTION
A first aspect of the invention is a dual-purpose target- analyte sensitive material capable of being effectively deployed as (i) a probe to measure target- analyte concentrations in both gaseous and aqueous environments, and (ii) cell culture scaffolding from which spatial distribution of oxygen concentration within the cell culture indicative of cell microenvironment can be measured and mapped. In a first embodiment the material consists only of a porous wettable scaffolding impregnated with an optically-active, target- analyte sensitive dye in the absence of any other components that would materially affect functionality of the material as a probe and a cell microenvironment spatial distribution indicator. In a second embodiment the material includes at least a porous wettable scaffolding impregnated with an optically-active, target- analyte sensitive dye. In both embodiments the porous scaffolding is a polymer having a hydrophobic polymer backbone
with hydrophilic pendant groups or hydrophilic pendant chains, and the optically-active, target- analyte sensitive dye is a hydrophobic, photoluminescent, target- analyte sensitive dye.
The porous scaffolding can be a microporous fibrous membrane or a microporous monolithic membrane, made of a suitable polymer such as polyethylene, polypropylene or polystyrene. It is preferably designed and constructed for culturing of eukaryotic or prokaryotic cells.
A second aspect of the invention is a method of manufacturing a material according to the first aspect of the invention. The method includes the steps of (A) dissolving the hydrophobic, optically- active, target-analyte sensitive dye in a blend of water and a water- miscible organic solvent to form a solution, (B) soaking the scaffolding with the solution, (C) preferentially depleting the organic solvent from the solution in which the scaffolding is soaking, whereby the hydrophobic optically-active, target-analyte sensitive dye preferentially migrates to the hydrophobic backbone of the scaffolding, and (D) drying the scaffolding after depleting the organic solvent to form a wettable target-analyte sensitive material.
A third aspect of the invention is a method for measuring concentration of a target-analyte in an aqueous sample employing a probe constructed from material according to the first aspect of the invention. The method includes the steps of (A) obtaining a probe constructed from the target-analyte sensitive material according to the first aspect of the invention, (B) placing the probe into direct fluid communication with an aqueous test sample whereby the sample wets the probe, and (C) ascertaining target-analyte concentration within the aqueous test sample by: (i) exposing the probe to excitation radiation to create an excited probe, (ii) measuring radiation emitted by the excited probe, and (iii) converting the measured emission to a target-analyte concentration based upon a known conversion algorithm.
A fourth aspect of the invention is a method for measuring concentration of a target-analyte within an enclosed space employing a probe constructed from material according to the first aspect of the invention. The method includes the steps of (A) obtaining a probe constructed from the target-analyte sensitive material according to the first aspect of the invention, (B) placing the probe within a space, (C) enclosing the space, and (D) ascertaining target-analyte concentration within the enclosed space by: (i) exposing the probe to excitation radiation to create an excited probe, (ii) measuring radiation emitted by the excited probe, and (iii) converting the measured emission to a target-analyte concentration based upon a known conversion algorithm.
A fifth aspect of the invention is a method for monitoring changes in target- analyte concentration in an aqueous test sample employing a probe constructed from material according to the first aspect of the invention. The method includes the steps of (A) obtaining a probe constructed from the target- analyte sensitive material according to the first aspect of the invention, (B) placing the probe into direct fluid communication with an aqueous test sample whereby the sample wets the probe, (C) ascertaining target- analyte concentration within the aqueous test sample over time by: (i) taking at least two emission measurements over time, each measurement comprising the steps of: (1) exposing the probe to excitation radiation to create an excited probe, and (2) measuring radiation emitted by the excited probe, (ii) measuring passage of time between at least two of the emission measurements to determine a time interval between identified emission measurements, and (iii) converting at least the identified emission measurements to a target-analyte concentration based upon a known conversion algorithm, and (E) reporting at least one of (i) at least the two ascertained target-analyte concentrations and the time interval between those reported concentrations, and (ii) a rate of change in target-analyte concentration within the aqueous test sample calculated from data obtained in step (C).
A sixth aspect of the invention is a method for monitoring changes in target-analyte concentration within an enclosed space employing a probe constructed from material according to the first aspect of the invention. The method includes the steps of (A) obtaining a probe constructed from the target-analyte sensitive material according to the first aspect of the invention, (B) placing the probe within a space, (C) enclosing the space, (D) ascertaining target-analyte concentration within the enclosed space over time by: (i) taking at least two emission measurements over time, each measurement comprising the steps of: (1) exposing the probe to excitation radiation to create an excited probe, and (2) measuring radiation emitted by the excited probe, (ii) measuring passage of time between at least two of the emission measurements to determine a time interval between identified emission measurements, and (iii) converting at least the identified emission measurements to a target- analyte concentration based upon a known conversion algorithm, and (E) reporting at least one of (i) at least the two ascertained target-analyte concentrations and the time interval between those reported concentrations, and (ii) a rate of change in target-analyte concentration within the enclosed space calculated from data obtained in step (D).
A seventh aspect of the invention is a method for measuring and mapping differential oxygen concentrations within a cell culture employing a cell support structure constructed from
material according to the first aspect of the invention. The method includes the steps of (A) obtaining a cell support structure constructed from the target- analyte sensitive material according to the first aspect of the invention wherein the target- analyte is oxygen, (B) culturing cells within the cell support structure, and (C) ascertaining local oxygen concentrations within the cell support structure by: (i) exposing a discrete area of the cell support structure to excitation radiation to create an excited area on the structure, (ii) measuring radiation emitted by the excited discrete area, (iii) determining oxygen concentration within the excited discrete area, and (iv) optionally generating an image mapping the determined spatial distribution of oxygen over the cell support structure.
Definitions
As used herein, including the claims, the phrase "permeable" means a material that when formed into a 1 mil film has a target- analyte transmission rate of greater than 100 c3/m2 day when measured in accordance with ASTM D 3985 when the target analyte is oxygen and when measured in accordance with ASTM D 1434 when the target analyte is other than oxygen.
As used herein, including the claims, the phrase "highly permeable" means a material that when formed into a 1 mil film has a target- analyte transmission rate of greater than 1,000 c3/m2 day when measured in accordance with ASTM D 3985 when the target analyte is oxygen and when measured in accordance with ASTM D 1434 when the target analyte is other than oxygen.
As used herein, including the claims, the term "target-analyte" refers to a gaseous chemical substance, typically O2, NH3 or CO2, capable of proportionally altering an optical property of an optically-active material containing a photoluminescent dye.
As used herein, including the claims, the term "contactless interrogation", means interrogation without tangible physical contact with the interrogated device, whereby interrogation can occur through an intervening physical barrier.
As used herein, including the claims, the term "interrogation light" means electromagnetic radiation having a wavelength between 400 and 1000 nm, encompassing both excitation and emission light.
As used herein, including the claims, the term "wettable" means the ability of a water droplet to penetrate into the pores of a porous substrate as opposed to forming a bead at or proximate to the surface interface, effective for providing direct fluid communication between the water and the walls of the pores.
Description
Theory
The materials and methods described herein are based on the quenching of an optical property, typically photoluminescence, by a target-analyte, typically oxygen (O2). Luminescence encompasses both fluorescence and phosphorescence. Electromagnetic radiation in the ultraviolet or visible region is used to excite molecules to higher electronic energy levels. The excited molecules lose their excess energy by one of several methods. One of those methods is fluorescence. Fluorescence refers to the radiative transition of electrons from the first excited singlet state to the singlet ground state (Si .to So). The lifetime of fluorescence is relatively short, approximately 10"9 to 10"7 seconds. However, intersystem crossing from the lowest excited singlet state to the triplet state often occurs and is attributed to the crossing of the potential energy curves of the two states. The triplet state so produced may return to the ground state by a radiative process known as phosphorescence. Phosphorescence is the radiative relaxation of an electron from the lowest excited triplet state to the singlet ground state (Ti to So). Because the transition that leads to phosphorescence involves a change in spin multiplicity, it has a low probability and hence a relatively long lifetime of 10"4 to 10 seconds. Fluorescent and phosphorescent intensity and lifetime are known to change in a defined fashion relative to changes in the partial pressure of a target- analyte capable of quenching the photolumine scent molecules. Hence, the partial pressure of a target-analyte in fluid communication with a photolumine scent dye can be determined by measuring photoluminescence intensity, intensity ratio and/or lifetime.
Construction
A first aspect of the invention is a dual-purpose target-analyte sensitive material capable of being effectively deployed as (i) a probe to measure target-analyte concentrations in both gaseous and aqueous environments, and (ii) cell culture scaffolding from which spatial distribution of oxygen concentration within the cell culture indicative of cell
microenvironment can be measured and mapped. The material is capable of reporting the partial pressure, and thereby the concentration, of a target- analyte (PA).
The materials are preferably in the form of a membrane although other structures are possible. The materials are remotely interrogatable by optical means and autonomously positionable, thereby permitting the materials to be used for a wide variety of purposes.
When employed as a probe, the material is suitable for use in combination with a wide variety of assay vessels to quickly, easily and reliably measure and monitor changes in analyte concentration in an environment. The materials are particularly well suited for use as a probe to measure and monitor changes in target-analyte concentration in an enclosed environment in a non-invasive and non-destructive manner.
When employed as cell culture scaffolding, the material is suitable for use in combination with a wide variety of culturing vessels to quickly, easily and reliably measure and monitor localized changes in oxygen concentration throughout the scaffolding, from which spatial distribution of oxygen concentration within the cell culture indicative of cell microenvironment can be measured and mapped in a non-invasive and non-destructive manner.
The materials are sensitive to a target-analyte, such as O2, CO2, or CO. For purposes of simplicity only, and without intending to be limited thereto, the balance of the description shall reference O2 as the target-analyte since C -sensitive materials are the most commonly used types of optically active materials.
The material is comprises of a porous wettable scaffolding impregnated with an optically- active, oxygen sensitive dye.
The porous scaffolding is a polymer having a hydrophobic polymer backbone with hydrophilic pendant groups or hydrophilic pendant chains. The polymer should be (i) structurally stable, (ii) compatible with the solvent based oxygen sensitive coating solution during the coating process, (iii) compatible with the dry dye, (iv) inert when used in accordance with its intended use, and (v) oxygen permeable.
The size and density of hydrophilic pendant chains on the hydrophobic polymer backbone should be sufficient to render the scaffolding readily wettable throughout such that an aqueous test sample, including cells suspended in a cell culture medium, may promptly penetrate into the pores and into intimate sensing contact with the dye.
The material, when employed as a membrane, preferably has an overall thickness of 20 to 3000 μπι.
The scaffolding may be a non-woven, spun-bound, melt-bound or wet-laid membrane, preferrably formed from fibers having an average diameter of 1 to 50 μιη. The non-woven scaffolding preferably has an average pore diameter of 2 to 500 μιη and an average wall thickness between pores of 5 to 200 μιη. A nonexhaustive list of suitable materials for use as the porous nonwoven scaffolding includes specifically, but not exclusively backbones of polyethylene, polypropylene and copolymers thereof, with grafted hydrophilic pendant groups or side chains such as a carboxylic acid chain. A preferred carboxylic acid for use as the side chain is acrylic acid. Suitable nonwoven scaffolding is available from a number of sources including Freudenberg Nonwovens LP.
Alternatively, the scaffolding may be a monolithic microporous polymeric material, preferably having an average pore diameter of 10 to 500 μιη and an average wall thickness between pores of 2 to 100 μιη. A nonexhaustive list of suitable materials for use as the porous monolithic scaffolding includes specifically, but not exclusively backbones of polystyrene, polyurethane, and polycarbonate, with grafted hydrophilic pendant groups or side chains such as a carboxylic acid chain. A preferred carboxylic acid for use as the side chain is acrylic acid.
The scaffolding is impregnated with a hydrophobic, photoluminescent, oxygen sensitive dye. Contrary to customary practice, the dye is preferably impregnated sans any "embedding" polymer matrix in the dye solution.
One of routine skill in the art is capable of selecting a suitable oxygen- sensitive dye. Preferred photoluminescent indicator dyes are long-decay fluorescent or phosphorescent indicator dyes. For example, a nonexhaustive list of suitable P02 sensitive photoluminescent dyes includes specifically, but not exclusively, ruthenium(II)-bipyridyl and ruthenium(II)- diphenylphenanothroline complexes, porphyrin-ketones such as platinum(II)- octaethylporphine-ketone, platinum(II)-porphyrin such as platinum(II)- tetrakis(pentafluorophenyl)porphine, palladium(II)-porphyrin such as palladium(II)- tetrakis(pentafluorophenyl)porphine, phosphorescent metallocomplexes of tetrabenzoporphyrins, chlorins, azaporphyrins, and long-decay luminescent complexes of iridium(III) or osmium(II). Preferred P02 sensitive photoluminescent dyes include platinum- tetrakis(pentafluorophenyl)porphyrin (PtPFPP), palladium-
tetrakis(pentafluorophenyl)porphyrin (PdPFPP), platinum-octaethylporphyrin (PtOEP), palladium-octaethylporphyrin (PdOEP), platinum-octaethylporphyrinketone (PtOEPK), palladium-octaethylporphyrinketone (PdOEPK), platinum-tetraphenylporphyrin (PtTPP), platinum-benzoporphyrin, palladium-benzoporphyrin, ruthenium-diphenylphenanotroline bis(hexafluorophosphate) (Ru(dpp)3), and iridium-bis-3-(l,3-benzothiazol-2-yl)-7- (diethylamino)-2H-chromen-2-one acetylacetonate (Ir(Cs)2(acac)).
The oxygen- sensitive photoluminescent dye may be compounded with another dye sensitive to a different target-analyte, a target-analyte insensitive reference dye or other additives known to those of skill in the art.
Manufacture and Supply
The optically active material can be manufactured by any suitable technique. One technique is to (i) dissolve the dye in a suitable blend of water and a water-miscible organic solvent such as tetrahydrofurane, dimethylformamide or acetone, to form a solution, (ii) immersing and incubating the porous scaffolding in the solution, (iii) preferentially depleting the organic solvent from the solution, such as by heating to a temperature that favors evaporation of the organic solvent over water, whereby the dye preferentially migrates to the hydrophobic backbone of the scaffolding, and (iv) drying the scaffolding. The scaffolding may be washed and dried one or more times after the initial dyeing. It is preferred to preferentially dissipate at least 90% of the organic solvent before actively seeking to dissipate water in an effort to dry the scaffolding. Alternatively, the solution may be sprayed or spotted onto the scaffolding. The w/w ratio of water to organic solvent in the solution is preferably between 20:80 and 80:20. Generally, the concentration of dye in the solvent blend should be in the range of 0.01 to 5% w/w.
The scaffolding is preferably immersed in the solution for a duration sufficient to achieve at least 90 wt% penetration of the solution into the scaffolding relative the level of penetration achieved upon immersion for 24 hours, without dissolving or changing the structure of the scaffolding material.
The material may be sanitized or sterilized before or after packaging by any suitable means, such as heat, gamma irradiation or ethylene oxide, on order to avoid microbial contamination of a sample undergoing microbial testing with the material.
Use as a Probe
Measuring Concentration of Target-Analyte in an Aqueous Sample
The material can be used as a probe to quickly, easily, accurately and reliably measure the concentration of a target- analyte in an aqueous test sample {e.g., oxygen in waste water). The probe can be interrogated in the same manner as typical target- analyte sensitive photolumine scent materials are interrogated. Briefly, the material can be used to measure the concentration of a target- analyte in an aqueous test sample by (A) placing the probe into direct fluid communication with the aqueous test sample whereby the sample wets the probe, at a location where radiation at the excitation and emission wavelengths of the dye can be transmitted to and received from the material with minimal interference by the vessel in which the test sample is retained or the test sample itself, (B) interrogating the material with an interrogation device, and (C) converting the measured emissions to a target- analyte concentration within the aqueous test sample based upon a known conversion algorithm or look-up table. Conversion algorithms used to convert the measured emissions to a target- analyte concentration are well know to and readily developable by those with routine skill in the art.
Interrogation of the probe involves exposing the probe to excitation radiation to create an excited probe and, (ii) measuring radiation emitted by the excited probe from which analyte concentration of a test sample in fluid communication with the probe can be ascertained.
The radiation emitted by the excited material 10 can be measured in terms of photoluminescence intensity, intensity ratio and/or lifetime (rate of decay, phase shift or anisotropy), with measurement of lifetime generally preferred as a more accurate and reliable measurement technique when seeking to establish the extent to which the dye has been quenched by target- analyte.
Measuring Concentration of Target-Analyte Within an Enclosed Space
The material can be used as a probe to quickly, easily, accurately and reliably measure the concentration of a target- analyte in an environment {e.g., the sealed chamber 59 of an assay vessel 50 or the sealed chamber of a package containing a product susceptible to spoilage or deterioration). The probe can be interrogated in the same manner as typical target- analyte sensitive photoluminescent materials are interrogated. Briefly, the material is used to measure the concentration of a target- analyte in an environment by (A) placing the probe into fluid communication with the environment to be monitored {e.g., within the sealed chamber of an assay vessel containing a test sample) at a location where radiation at the excitation and
emission wavelengths of the dye can be transmitted to and received from the probe with minimal interference and without opening or otherwise breaching the integrity of the environment (e.g., without opening the assay vessel), (B) interrogating the probe with an interrogation device, and (C) converting the measured emissions to a target- analyte concentration within the environment based upon a known conversion algorithm or look-up table. Conversion algorithms used to convert the measured emissions to a target- analyte concentration are well know to and readily developable by those with routine skill in the art.
Interrogation of the probe involves exposing the probe to excitation radiation to create an excited probe and, (ii) measuring radiation emitted by the excited probe.
The radiation emitted by the probe can be measured in terms of photoluminescence intensity, intensity ratio and/or lifetime (rate of decay, phase shift or anisotropy), with measurement of lifetime generally preferred as a more accurate and reliable measurement technique when seeking to establish the extent to which the dye has been quenched by target- analyte.
Monitoring Changes in Tar get- Analyte Concentration in an Aqueous Test Sample
The material can be used as a probe to quickly, easily, accurately and reliably measure changes in target- analyte concentration in an aqueous test sample by (i) placing the probe into direct fluid communication with the aqueous test sample whereby the sample wets the probe, at a location where radiation at the excitation and emission wavelengths of the dye can be transmitted to and received from the material with minimal interference by the vessel in which the test sample is retained or the test sample itself, (B) ascertaining target- analyte concentration within the aqueous test sample over time by (i) repeatedly exposing the probe to excitation radiation over time, (ii) measuring radiation emitted by the excited probe after at least some of the exposures, (iii) measuring passage of time during the repeated excitation exposures and emission measurements, and (iv) converting at least some of the measured emissions to a target-analyte concentration based upon a known conversion algorithm or look-up table, and (C) reporting at least one of (i) at least two ascertained target-analyte concentrations and the time interval between those reported concentrations, and (ii) a rate of change in target-analyte concentration within the aqueous test sample calculated from data obtained in step (B). Conversion algorithms used to convert the measured emissions to a target-analyte concentration are well know to and readily developable by those with routine skill in the art.
The radiation emitted by the probe can be measured in terms of photoluminescence intensity, intensity ratio and/or lifetime (rate of decay, phase shift or anisotropy), with measurement of lifetime generally preferred as a more accurate and reliable measurement technique when seeking to establish the extent to which the dye has been quenched by target- analyte.
Monitoring Changes in Tar get- Analyte Concentration in an Enclosed Space
The material can be used as a probe to quickly, easily, accurately and reliably measure changes in target- analyte concentration in an enclosed environment by (i) placing the probe into fluid communication with the environment to be monitored at a location where radiation at the excitation and emission wavelengths of the dye can be transmitted to and received from the probe with minimal interference by the vessel enclosing the environment or the environment itself, and without physically accessing or otherwise breaching the integrity of the environment, (B) ascertaining target- analyte concentration within the environment over time by (i) repeatedly exposing the probe to excitation radiation over time, (ii) measuring radiation emitted by the excited probe after at least some of the exposures, (iii) measuring passage of time during the repeated excitation exposures and emission measurements, and (iv) converting at least some of the measured emissions to a target- analyte concentration based upon a known conversion algorithm or look-up table, and (C) reporting at least one of (i) at least two ascertained target- analyte concentrations and the time interval between those reported concentrations, and (ii) a rate of change in target- analyte concentration within the environment calculated from data obtained in step (B). Conversion algorithms used to convert the measured emissions to a target- analyte concentration are well know to and readily developable by those with routine skill in the art.
The radiation emitted by the probe can be measured in terms of photoluminescence intensity, intensity ratio and/or lifetime (rate of decay, phase shift or anisotropy), with measurement of lifetime generally preferred as a more accurate and reliable measurement technique when seeking to establish the extent to which the dye has been quenched by target- analyte.
Use of the probe to measure changes in target- analyte concentration in an enclosed environment is particularly well suited for use in a number of applications, including specifically but not exclusively (i) measurement of chemical activity of a test sample, (ii) measurement of biological activity of a test sample, (iii) presence/absence determination of a threshold concentration of aerobic microorganisms in a test sample, and (iv) enumeration of
aerobic microorganisms in a test sample as of the time the test sample is placed in the enclosed space.
Measuring and Mapping Differential Oxygen Concentrations Within a Cell Culture
The material can be used as a support scaffolding for the culturing of cells, from which the spatial distribution of differences in cell microenvironment throughout the culture can be ascertained and mapped. The method includes the steps of (i) culturing cells (e.g., eukaryotic or prokaryotic cells) within a cell support structure comprising the material, (ii) interrogating the support scaffolding with an interrogation device capable of measuring spatial distribution of radiation emitted by the excited structure, and (iii) generating an image mapping the measured spatial distribution of radiation.
Interrogation of the support scaffolding involves exposing the support scaffolding to excitation radiation to create an excited support scaffolding and, (ii) detecting and measuring or visually depicting difference in localized radiation emitted by the excited probe.
Fluorescence microscopy, including wide-field, laser scanning and two-photon microscopy devices, are suitable for interrogating the support scaffolding and generating an image depicting spatial distribution of radiation emitted by the excited structure. Other devices may also be employed. The device preferably generates an image, either a two-dimensional image or a three-dimensional image, indicating at least those areas having an oxygen concentration below a threshold value indicative of hypoxic cells within the area.
When measured, the radiation emitted by the excited support scaffolding can be measured in terms of photoluminescence intensity, intensity ratio and/or lifetime (rate of decay, phase shift or anisotropy), with measurement of lifetime generally preferred as a more accurate and reliable measurement technique when seeking to establish the extent to which the dye has been quenched by oxygen, correlating to the extent to which oxygen has been depleted by the presence of viable cells proximate the area.
EXAMPLES
Example 1
(Manufacture of O2 Sensitive Material)
A 15 x 30 mm sheet of spun-bound polypropylene grafted with acrylic chains is soaked in 10 mL of a tetrahydrofuran- water (70:30 % w/w) solution containing 0.02 mg/ml PtPFPP dye in a capped vessel for lh at 60°C. The contents of the vessel were then placed under moderate vacuum (50 mmHg) on a rotary evaporator to gradually and preferentially evaporate the THF (~lh at 40°C).
Increased polarity of the solvent (pure water at the end) forced the hydrophobic dye molecules to migrate into the hydrophobic polypropylene backbone of the polymer forming the sheet. Thus, efficient and uniform impregnation of the sheet with the dye is achieved.
After evaporation of the THF, the material was subsequently dried in an oven at 70°C for 16 hours and then processed into individual 02 sensitive probes suitable for use in detecting 02 concentrations in both gaseous and aqueous liquid samples.
Example 2
(Manufacture of O2 Sensitive Scaffolds)
Disks of hydrophylic microporous polystyrene scaffolds (15 mm in diameter, Reinnervate) are placed in the wells of 12-well plates (Sarstedt), covered with 2 mL of an acetone-water (70:30 % w/w) solution containing 0.05 mg/ml PtPFPP dye and incubated for 2 hours at 60°C to evaporate organic solvent. The incubated scaffolds were quickly rinsed with 50% ethanol, then with sterile water and dried to form phosphorescent O2 sensitive scaffolds.
These phosphorescent O2 sensitive scaffolds are used to culture mammalian cells (mouse embryonic fibroblasts in RPMI medium) and monitor oxygenation of cells in different parts of the scaffold by live cell fluorescent imaging. Regions of the scaffold with cells producing high optical signals (phosphorescence lifetime or intensity) correspond to hypoxic zones.
Claims
1. An oxygen sensitive material, comprising a microporous scaffolding selected from a microporous fibrous membrane or a microporous monolithic membrane impregnated with a phosphorescent oxygen sensitive dye, wherein:
(bb) the microporous scaffolding is a polymer having a hydrophobic, oxygen
permeable, polymer backbone with hydrophilic pendant groups or hydrophilic pendant chains that render the microporous scaffolding wettable, and
(cc) the phosphorescent oxygen sensitive dye is a hydrophobic dye and is
predominantly located in the hydrophobic polymer backbone
2. An oxygen sensitive material, consisting essentially of a microporous scaffolding selected from a microporous fibrous membrane or a microporous monolithic membrane impregnated with a phosphorescent oxygen sensitive dye, wherein:
(a) the microporous scaffolding is a polymer having a hydrophobic, oxygen
permeable, polymer backbone with hydrophilic pendant groups or hydrophilic pendant chains that render the microporous scaffolding wettable, and
(b) the phosphorescent oxygen sensitive dye is a hydrophobic dye and is located in the hydrophobic polymer backbone.
3. The material of any one of claims 1 and 2 wherein the membrane has an overall
thickness of 20 to 3000 μιη.
4. The material of any one of claims 1 to 3 wherein the microporous membrane has an average pore diameter of 2 to 500 μιη, and is capable of actingas a scaffold for culturing adherent eukaryotic or prokaryotic cells in three-dimensional space.
5. The material of any one of claims 1 and 2 wherein the membrane is a non- woven, spun-bound, melt-bound or wet-laid membrane formed from fibers having an average diameter of 1 to 50 μιη.
6. The material of claim 5 wherein the pores have an average wall thickness between pores of 5 to 200 μιη and the polymer backbone is selected from polyethylene, polypropylene and copolymers thereof.
7. The material of any one of claims 1 and 2 wherein the microporous monolithic membrane has an average pore diameter of 10 to 500 μιη and an average wall thickness between pores of 2 to 100 μιη.
8. The material of claim 7 wherein the polymer of the microporous monolithic
membrane is selected from polystyrene, polyurethane, and polycarbonate.
9. The material of any preceding Claim wherein the scaffolding has hydrophilic pendant carboxylic acid chains.
10. The material of claim 9 wherein the pendant carboxylic acid chains are pendant
acrylic acid chains.
11. The material of claim 8 wherein the polymer backbone is polystyrene and the
scaffolding has pendant sulfonic acid groups.
12. The material of any preceding Claim wherein the phosphorescent oxygen sensitive dye dye has a responsive optical characteristic that changes in response to changes in the concentration or partial pressure of oxygen to which the sensor material is exposed.
13. The material of claim 12 wherein the responsive optical characteristic is at least one of photoluminescence lifetime, photoluminescence intensity and intensity ratio.
14. The material of claim 12 or 13 wherein the oxygen- sensitive phosphorescent dye is an oxygen sensitive photolumine scent transition metal complex selected from the group consisting of a platinum-tetrakis(pentafluorophenyl)porphyrin (PtPFPP), a palladium- tetrakis(pentafluorophenyl)porphyrin (PdPFPP), a platinum-octaethylporphyrin (PtOEP), a palladium-octaethylporphyrin (PdOEP), a platinum- octaethylporphyrinketone (PtOEPK), a palladium-octaethylporphyrinketone
(PdOEPK), a platinum- tetraphenylporphyrin (PtTPP), a platinum- tetrabenzoporphyrin, a palladium-tetrabenzoporphyrin, a ruthenium-
diphenylphenanotroline bis(hexafluorophosphate) (Ru(dpp)3), and an iridium-bis-3- ( 1 ,3-benzothiazol-2-yl)-7-(diethylamino)-2H-chromen-2-one acetylacetonate
(Ir(Cs)2(acac)).
15. A method of manufacturing an oxygen sensitive material according to any preceding Claims comprising the steps of:
(a) dissolving the hydrophobic, oxygen sensitive phosphorescent dye in a blend of water and a water-miscible organic solvent to form a solution,
(b) soaking the microporous scaffolding with the solution,
(c) preferentially depleting the organic solvent from the solution in which the scaffolding is soaking, whereby the hydrophobic oxygen sensitive phosphorescent dye preferentially migrates to the hydrophobic backbone of the scaffolding, and
(d) drying the microporous scaffolding after depleting the organic solvent to form a wettable oxygen sensitive material.
16. The method of claim 15 wherein (i) the microposous scaffolding is soaked with the solution for a duration sufficient to achieve at least 90 wt penetration of the solution into the microporous scaffolding relative to penetration achievable upon soaking for 24 hours, and (ii) the method further includes the step of washing the microporous scaffolding after depleting the organic solvent.
17. The method of claim 15 or 16 wherein the solution has a w/w ratio of water to organic solvent of between 20:80 and 80:20.
18. The method of claim 15, 16 or 17 wherein the organic solvent is selected from the group consisting of tetrahydrofurane, dimethylformamide, ethanol and acetone.
19. The method of any of Claims 15 to 18 wherein at least 90% of the organic solvent is dissipated in step (c).
20. The method of claim 19 wherein the organic solvent is evaporated in step (c) without any significant precipitation of the hydrophobic phosphorescent dye.
21. A method for measuring oxygen concentration in an aqueous sample, comprising the steps of:
(a) obtaining a probe constructed from the oxygen sensitive material of any of Claims 1 to 14,
(b) placing the probe into direct fluid communication with an aqueous test sample whereby the sample wets the probe, and
(c) ascertaining oxygen concentration within the aqueous test sample by:
(i) exposing the probe to excitation radiation to create an excited probe,
(ii) measuring radiation emitted by the excited probe, and
(iii) converting the measured emission to an oxygen concentration based upon a known conversion algorithm.
22. A method for measuring concentration of oxygen within an enclosed space,
comprising the steps of:
(a) obtaining a probe constructed from the oxygen sensitive material of any of Claims 1 to 14,
(b) placing the probe within a space,
(c) enclosing the space, and
(d) ascertaining oxygen concentration within the enclosed space by:
(i) exposing the probe to excitation radiation to create an excited probe,
(ii) measuring radiation emitted by the excited probe, and
(iii) converting the measured emission to an oxygen concentration based upon a known conversion algorithm.
23. The method of claim 22 wherein (i) the space is enclosed within a receptacle, and (ii) the probe is contactlessly interrogated through the receptacle.
24. A method for monitoring changes in oxygen concentration in an aqueous test sample, comprising the steps of:
(a) obtaining a probe constructed from the oxygen sensitive material of any of Claims 1 to 14,
(b) placing the probe into direct fluid communication with an aqueous test sample whereby the sample wets the probe,
(c) ascertaining oxygen concentration within the aqueous test sample over time by:
(i) taking at least two emission measurements over time, each
measurement comprising the steps of:
(1) exposing the probe to excitation radiation to create an excited probe, and
(2) measuring radiation emitted by the excited probe,
(ii) measuring passage of time between at least two of the emission
measurements to determine a time interval between identified emission measurements, and
(iii) converting at least the identified emission measurements to an oxygen concentration based upon a known conversion algorithm, and
(d) reporting at least one of (i) at least the two ascertained oxygen concentrations and the time interval between those reported concentrations, and (ii) a rate of change in oxygen concentration within the aqueous test sample calculated from data obtained in step (c).
A method for monitoring changes in oxygen concentration within an enclosed space, comprising the steps of:
(a) obtaining a probe constructed from the oxygen sensitive material of any of Claims 1 to 14,
(b) placing the probe within a space,
(c) enclosing the space,
(d) ascertaining oxygen concentration within the enclosed space over time by:
(i) taking at least two emission measurements over time, each
measurement comprising the steps of:
(1) exposing the probe to excitation radiation to create an excited probe, and
(2) measuring radiation emitted by the excited probe,
(ii) measuring passage of time between at least two of the emission
measurements to determine a time interval between identified emission measurements, and
(iii) converting at least the identified emission measurements to an oxygen concentration based upon a known conversion algorithm, and
(e) reporting at least one of (i) at least the two ascertained oxygen concentrations and the time interval between those reported concentrations, and (ii) a rate of change in oxygen concentration within the enclosed space calculated from data obtained in step (d).
26. The method of claim 25 wherein the method is applied to achieve at least one of (i) a measurement of chemical activity of the test sample, (ii) a measurement of biological activity of the test sample, (iii) a presence/absence determination of a threshold concentration of aerobic microorganisms in the test sample, and (iv) an enumeration of aerobic microorganisms in the test sample at the time the test sample is placed in the space.
27. A method for measuring and mapping differential oxygen concentrations within a cell culture, comprising the steps of:
(a) obtaining a cell support structure constructed from the oxygen sensitive
material of any of Claims 1 to 14,
(b) culturing cells within the cell support structure, and
(c) ascertaining local oxygen concentrations within the cell support structure by:
(i) exposing a discrete area within the cell support structure to excitation radiation to create an excited area on the structure,
(ii) measuring radiation emitted by the excited discrete area,
(iii) determining oxygen concentration within the excited discrete area, and
(iv) optionally generating an image mapping the determined spatial
distribution of oxygen over the cell support structure.
28. The method of claim 27 wherein an image is generated that visually identifies those discrete areas within the cell support structure having an oxygen concentration below a threshold value indicative of hypoxic cells within the discrete area.
29. The method of claim 27 or 28 wherein the image is a 2-dimensional image.
30. The method of claim 27 or 28 wherein the image is a 3-dimensional image
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| Application Number | Priority Date | Filing Date | Title |
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| EP13171181 | 2013-06-10 | ||
| EP13171181.4 | 2013-06-10 |
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| WO2014198669A1 true WO2014198669A1 (en) | 2014-12-18 |
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| PCT/EP2014/061857 WO2014198669A1 (en) | 2013-06-10 | 2014-06-06 | An oxygen sensitive material, and use thereof to sense oxygen in three-dimensional spaces |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110678758A (en) * | 2017-05-10 | 2020-01-10 | 卢克塞尔生物科学公司 | Real-time oxygen control of cells or the microenvironment around cells |
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