EP1915649A2 - Dispositif d'indication de stimulus utilisant des gels polymeres - Google Patents

Dispositif d'indication de stimulus utilisant des gels polymeres

Info

Publication number
EP1915649A2
EP1915649A2 EP06787468A EP06787468A EP1915649A2 EP 1915649 A2 EP1915649 A2 EP 1915649A2 EP 06787468 A EP06787468 A EP 06787468A EP 06787468 A EP06787468 A EP 06787468A EP 1915649 A2 EP1915649 A2 EP 1915649A2
Authority
EP
European Patent Office
Prior art keywords
stimulus
compartment
indicating device
gel
predetermined
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP06787468A
Other languages
German (de)
English (en)
Other versions
EP1915649A4 (fr
Inventor
Rel S. Ambrozy
Jade Litcher
Raymond C. Jones
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Prasidiux LLC
Original Assignee
Prasidiux LLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US11/414,254 external-priority patent/US9063015B2/en
Application filed by Prasidiux LLC filed Critical Prasidiux LLC
Publication of EP1915649A2 publication Critical patent/EP1915649A2/fr
Publication of EP1915649A4 publication Critical patent/EP1915649A4/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G04—HOROLOGY
    • G04F—TIME-INTERVAL MEASURING
    • G04F1/00—Apparatus which can be set and started to measure-off predetermined or adjustably-fixed time intervals without driving mechanisms, e.g. egg timers
    • G04F1/04—Apparatus which can be set and started to measure-off predetermined or adjustably-fixed time intervals without driving mechanisms, e.g. egg timers by movement or acceleration due to gravity
    • G04F1/06—Apparatus which can be set and started to measure-off predetermined or adjustably-fixed time intervals without driving mechanisms, e.g. egg timers by movement or acceleration due to gravity by flowing-away of a prefixed quantity of fine-granular or liquid materials, e.g. sand-glass, water-clock
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
    • G01K3/00—Thermometers giving results other than momentary value of temperature
    • G01K3/02—Thermometers giving results other than momentary value of temperature giving means values; giving integrated values
    • G01K3/04—Thermometers giving results other than momentary value of temperature giving means values; giving integrated values in respect of time

Definitions

  • the present invention relates to a stimulus-indicating device. More particularly, the 5 present invention relates to an apparatus and method for evidencing when a product has been exposed to a designated stimulus for a certain period of time.
  • the useful life of a perishable product is a function of o its cumulative exposure to a harmful stimulus over a period of time.
  • the types of stimuli that advance the degradation of stimulus-sensitive products over time include not only temperature, but also light, pH, humidity, electromagnetic radiation and radiation.
  • the useful life of a temperature sensitive product is a function of its cumulative time-temperature exposure - a combination of the temperature to which a product is exposed and the duration 5 of the exposure.
  • a malaria vaccine will degrade faster below 2°C than if stored between the range of 3 0 C to 7°C.
  • Stimulus perishable products susceptible to degradation due to cumulative time- stimulus exposure include, but are not limited to, food, food additives, chemicals, biological materials, drugs, cosmetics, photographic supplies and vaccines.
  • Many manufacturers mark their products with printed expiration dates in an attempt to provide an indication of when the 5 useful life of a perishable product lapses. However, these dates are only estimates and may be unreliable because they are based on assumptions about the stimulus history of the product that may not be true with respect to the particular unit or product in the package on which the expiration date appears.
  • manufacturers compute expiration dates by assuming that the product will be kept within a specified stimulus range during the product's useful life. o
  • the manufacturer cannot always predict or control the stimulus exposure of a product through each step of the supply chain that delivers the product to the consumer. If the product is actually exposed to stimulus higher than those on which the expiration date is based, the perishable product may degrade or spoil before the printed expiration date. When this happens, the expiration date may mislead the consumer into believing that the perishable 5 product is still usable when, in fact, its useful life has lapsed.
  • Marking a stimulus sensitive product with an expiration date is useful nonetheless, because often a visual inspection of the perishable product does not warn a potential user that the exposure of the product to a harmful stimulus has caused it to degrade or spoil.
  • time-stimulus indicators currently available, most are focused on o temperature, and not on the other types of stimuli. Additionally, many of these time- temperature indicators require the active agents to be kept separate from one another until the indicator is attached to the product it is monitoring. If the active ingredients are not kept separate they will begin to interact prematurely, thereby giving a premature indication of spoilage. As a result, these types of indicators require manual activation, but manual 5 activation is not always feasible when the indicator is being used with a product that is mass- produced in high- volume.
  • an indicator that indicates when a stimulus sensitive product has been exposed to a deleterious stimulus extreme for a pre-determined amount of time.
  • a time-stimulus indicator that does not contain active agents that will o begin to interact prior to being attached to the product being monitored, thereby resulting in false indications of spoilage.
  • a stimulus indicator that does not require manual activation, and a stimulus indicator that can provide an irreversible indication of exposure to a predetermined stimulus extreme.
  • the present invention is directed to a stimulus indicator device, which substantially overcomes one or more of the above-mentioned problems arising from limitations and disadvantages of the related art.
  • one embodiment of the invention is a device including a first compartment and a second compartment separated by a semi-permeable membrane, with the first compartment containing a stimulus sensitive gel.
  • a display portion is provided through which a color change can be seen when the stimulus sensitive gel changes volume by shrinking in reaction to a predetermined stimulus. As the gel shrinks in response to the predetermined stimulus, a liquid within the stimulus sensitive gel is expelled in the first compartment, and passes into the second compartment though the semi-permeable membrane that separates the two compartments.
  • the semi-permeable membrane only allows the liquid to pass in one direction, the liquid is trapped in the second compartment, resulting in a constant volume of liquid and gel in the first compartment and thereby preventing the gel from re-expanding even when the predetermined stimulus condition is removed.
  • another embodiment of the invention is a device that indicates when a stimulus sensitive product has potentially or conclusively undergone a physical change in response to exposure to a predetermined stimulus extreme.
  • another embodiment of the invention is a device that indicates when a stimulus sensitive product has potentially or conclusively undergone a physical change in response to exposure to a predetermined stimulus extreme over a predetermined period of time.
  • Fig. IA is a side cross-sectional view of an embodiment of the invention before exposure to a predetermined stimulus extreme
  • Fig. IB is a side cross-sectional view of the embodiment in Fig. IA after exposure to a predetermined stimulus extreme;
  • Fig. 2 A is a top view of a stimulus-indicating device with two compartments connected by a nozzle portion and the stimulus-indicating gel in the expanded non-stimulated state;
  • Fig. 2B is a top view of a stimulus-indicating device with two compartments connected by a nozzle portion and the stimulus-indicating gel in the contracted stimulated state.
  • the same embodiments could be used for other stimuli such as humidity, radiation, visible light, etc.
  • the three broad areas include: i) the use of semi-permeable membranes; ii) physical constriction of the gels; and iii) the use of dyes. These embodiments may be used alone or in combination.
  • the first embodiment as shown in Figs. IA and IB, utilizes a semi-permeable membrane barrier that separates the expelled water from the gel as the swollen gel shrinks. Such a membrane would prevent the shrunken gel from later reacting with the expelled water, thus preventing expansion of the gel back to its original size.
  • a semi-permeable membrane 300 separates two adjacent compartments, first compartment 302 and second compartment 304.
  • first compartment 302 a portion of swollen gel 310 is visible in the indicator window 312, with the remaining portion being hidden from view.
  • the swollen gel 310 may be based on polyacrylic acid (PAA), polyacrylaniide (PAAm), and its variations such as n-isopropylacrylamide (NIPAAm), and their derivatives.
  • PAA polyacrylic acid
  • PAAm polyacrylaniide
  • NIPAAm n-isopropylacrylamide
  • these polymer gels undergo a significant change in 5 volume in response to a range of stimuli, including temperature, solvent composition, pH, ionic strength etc.
  • the "trigger" temperature at which a gel changes volume can be "tuned” to a particular value by adding salts, surfactants, or other substances to the gel matrix.
  • a further concept inherent in these polymer gels is the directionality of the o temperature-induced volume changes.
  • Some polymer gels e.g., PAAm
  • UCST Ultra Critical Solution Temperature
  • other polymer gels e.g., NIPAAm
  • UCST or LCST behavior depends on the chemical structure. Many s examples of both kinds of polymer are known in the literature.
  • the swollen gel 310 may contain a suitable dye or additive to color the gel, for example, green. The net result is to enable the green color to be exposed through the indicator window 312 so long as the perishable product stayed within safe limits.
  • the temperature sensitive product is exposed to the transition temperature, the swollen gel 310 o will shrink (see reference numeral 320 in Fig. IB) and not be visible through the indicator window 312.
  • the transition temperature trigger may be when the gel is heated or cooled to a designated temperature, depending on whether the polymer gel was of the LCST or UCST type. In either case, as the swollen gel 310 shrinks, the water (or other liquid or mixture) 314 in the gel matrix is expelled. Accordingly, as shown in Fig.
  • the expelled water 314 would 5 pass through the semi-permeable membrane 300 and be deposited in the empty second compartment 304.
  • the shrinking of the gel exposes the colored indicator spot 316 through the indicator window 312 (which would now present a red color, for example), indicating a harmful temperature exposure as shown in Fig. IB.
  • the shrunken gel 320 would remain in that state, o even if the temperature returns to the "good" range, because the shrunken gel 320 could not come into contact with the expelled water 314 to expand back to its original state. Because the semi-permeable membrane 300 only allows the liquid to pass in one direction, the liquid is trapped in the second compartment 304, resulting in a constant volume of liquid and gel in the first compartment 302 and thereby preventing the gel from re-expanding even when the predetermined stimulus condition is removed. Preferably the gel is held in place in the first compartment 302 by being attached at a point opposite the indicator window 312.
  • a suitable water-absorbing (hygroscopic) substance such as a silica gel, could also be added to the empty second compartment 304 to ensure the expelled water 314 is used up and not be allowed to pass back through the semi-permeable or permeable membrane to allow the gel to expand.
  • a suitable water-absorbing (hygroscopic) substance such as a silica gel
  • it could also expel a dye that discolors a gauze or litmus-type substrate, as opposed to having a pre-existing indicator spot 316.
  • the discolored gauze-type substrate would produce a different visual color as viewed through the swollen gel 310, thereby confirming exposure to a harmful temperature.
  • the dye could be used either with or without the membrane.
  • Figs. 2A and 2B provide a top-down view of stimulus-indicating device 200.
  • This embodiment of the stimulus sensitive device 200 consists of a first compartment 224 and a second compartment 225.
  • the first compartment 224 and the second compartment 225 are additionally formed and differentiated from one another by a nozzle portion 237.
  • What is important is that the water or other suitable liquid 314 described above that interacts with the gel 310 flow freely between the first compartment 224 and the second compartment 225 through the nozzle portion 237, while the nozzle portion 237 provides a constricting region to any subsequent attempt by the shrunken gel 320 to expand back into the first compartment 224.
  • the indicator spot 316 that is contained in the first compartment 224 is colored a first color, such as red.
  • a stimulus extreme such as temperature
  • the gel 310 is in its expanded state (contour shown by heavy dashed-lines 226e) and resides in both the first compartment 224 and the second compartment 225.
  • the gel 310 prior to being exposed to a critical temperature extreme the gel 310 completely covers the indicator spot 316 positioned inside the first compartment 224.
  • the gel 310 that in its expanded state 226e is present in both the first compartment 224 and the second compartment 225 is designed to be sensitive to a stimulus, and reacts to such stimulus by undergoing a noticeable decrease in volume.
  • the gel 310 when the gel 310 is exposed to a predetermined stimulus, it shrinks in volume, and therefore shrinks in size.
  • the decrease in volume of the gel in this embodiment can be by any amount so long as it is noticeable, preferably the decrease in volume of the gel 310 in this embodiment is between at least a 1/10 reduction in original volume up to 500 times decrease in original volume.
  • the gel 310 which changes volume when it is exposed to a predetermined stimulus can be manufactured as described in at least the following references: U.S. Patent Nos. RE35,068, 5,403,893 and 4,732,930 to Tanaka et al. See also, Harmon et al., "A microfluidic actuator based on thermoresponsive hydrogels", Polymer 44 (2003) at 4547-4556.
  • the gel 310 will remain stable at its manufactured volume until it is exposed to the predetermined stimulus.
  • the gel 310 is designed to work in conjunction with water or other suitable liquid 314 that aids in its volume change.
  • the first compartment 224 and the second compartment 225 are interconnected so that the liquid 314 flows freely between the first compartment 224 and the second compartment 225.
  • the gel 320 will have collapsed (contour shown by heavy dashed-lines 226c) to a point where the second color of the gel 310 is no longer visible because it has receded from the indicator window 312 positioned above the first compartment 224.
  • the first color e.g., red
  • the indicator spot 316 in the first compartment 224 is visible to the user through the indicator window 312. It is the appearance of this second color in the indicator window 312 that indicates to the user that the stimulus sensitive product to which the stimulus-indicating device 200 is attached, has been exposed to a deleterious stimulus extreme, and has either probably or definitely spoiled.
  • the gel 320 is held in place in the second compartment 225 by being attached at a point opposite the indicator window 312.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Investigating Or Analysing Materials By The Use Of Chemical Reactions (AREA)
  • Devices For Indicating Variable Information By Combining Individual Elements (AREA)
  • Measurement Of Unknown Time Intervals (AREA)

Abstract

L'invention concerne un dispositif d'indication de stimulus. L'invention concerne plus particulièrement un appareil et un procédé permettant de mettre en évidence l'exposition d'un produit à un stimulus désigné pendant une certaine durée.
EP06787468A 2005-07-14 2006-07-14 Dispositif d'indication de stimulus utilisant des gels polymeres Withdrawn EP1915649A4 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US69898405P 2005-07-14 2005-07-14
US11/414,254 US9063015B2 (en) 2005-04-29 2006-05-01 Stimulus indication employing polymer gels
PCT/US2006/027564 WO2007009103A2 (fr) 2005-07-14 2006-07-14 Dispositif d'indication de stimulus utilisant des gels polymeres

Publications (2)

Publication Number Publication Date
EP1915649A2 true EP1915649A2 (fr) 2008-04-30
EP1915649A4 EP1915649A4 (fr) 2009-06-24

Family

ID=37638005

Family Applications (1)

Application Number Title Priority Date Filing Date
EP06787468A Withdrawn EP1915649A4 (fr) 2005-07-14 2006-07-14 Dispositif d'indication de stimulus utilisant des gels polymeres

Country Status (2)

Country Link
EP (1) EP1915649A4 (fr)
WO (1) WO2007009103A2 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2552167A (en) 2016-07-11 2018-01-17 Intray Ltd Time temerature indicator label

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004062699A1 (fr) * 2003-01-11 2004-07-29 Reckitt Benckiser (Uk) Limited Dispositif de régénération d'air

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6741523B1 (en) * 2000-05-15 2004-05-25 3M Innovative Properties Company Microstructured time dependent indicators
US6614728B2 (en) * 2001-09-14 2003-09-02 3M Innovative Properties Company Time-temperature integrating indicator
ATE434781T1 (de) * 2002-04-03 2009-07-15 3M Innovative Properties Co Produkte zur anzeige der zeit oder zeit- temperatur

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004062699A1 (fr) * 2003-01-11 2004-07-29 Reckitt Benckiser (Uk) Limited Dispositif de régénération d'air

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of WO2007009103A2 *

Also Published As

Publication number Publication date
EP1915649A4 (fr) 2009-06-24
WO2007009103A3 (fr) 2007-07-12
WO2007009103A2 (fr) 2007-01-18

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