WO2010114519A1

WO2010114519A1 - Evanescent field plasmon resonance detector

Info

Publication number: WO2010114519A1
Application number: PCT/US2009/038916
Authority: WO
Inventors: Lee James Johnson
Original assignee: The Government Of The United States Of America, As Represented By The Secretary Of The Navy
Priority date: 2009-03-31
Filing date: 2009-03-31
Publication date: 2010-10-07

Abstract

An embodiment of the invention includes a device comprising a plurality of nanoparticles and a noble metal film comprising a first side and a second side, the plurality of nanoparticles being located on the second side of said metal film. The device also includes a binding sample contacting the second side of said metal film and a light- sensitive, semiconductor detector array located at a distance less than 200 nanometers from the first side of the metal film.

Description

K.I . ATK.

This application claims priority to U.S. Provisional Patent Application Serial No. 61/041 ,341 , entitled "E VA NESCENT FlE LD PLASMON RESONANCE DETECTOR," to Johnson.

This invention relates generally to a device for detecting a Surface Plasmon Resonance peak, and, more particularly, to a semiconductor detector for detecting a Surface Plasmon Resonance peak.

Surface plasmon resonance requires the coupling of incident light to oscillations in the conducting electrons in the surface of a metal. These oscillations are called plasmons. The plasmons yield an evanescent iϊeld which propagates on either side of the surface and the resonant wavelength at which maximal absorption occurs is sensitive to the index of refraction of the surrounding medium. The coupling of the incident light to the plasmon modes of the metal is typically achieved in a Krelschmann Prism configuration with a metal coated prism yielding total internal reflection at a specific angle of incident light. An example of the Kretschmann Prism configuration is shown in FIG. 1. The Kretschmann Prism is the prism 10 located opcratively between a light source 60 and a light detector 20. If the prism 10 were coated with an infinitely high index of refraction, then total internal reflection would occur for all light reflected at angles greater than a critical angle, and all of the light reflected toward the surface of the prism would be reflected away from the surface. If light is totally internally reflected off the inside of prism 10, then some of the light will exist outside of the surface of the prism. This light is called the evanescent wave.

Instead of coating the prism with a material that approximates an infinite refractive index and thus allows for almost no evanescent wave, the prism 10 is attached to a sensor chip 30 via a thin layer of metal 40 and glass 50. A sample holder 70 is attached to the sensor chip 30. The sea of free electrons in the metal 40 has waves in it. Motion of electromagnetic waves in the surface of the metal is called the surface plasmon. When the surface plasmon has similar properties to the evanescent wave, the surface plasmon and the evanescent wave couple. This phenomenon is called Surface Plasmon Resonance, or SPR.

When SPR occurs, it uses energy. Thus, the intensity of light reflected back from {he surface is less than that incident on the surface. This intensity can be measured to determine when SPR has occurred. If a sensor chip can be fabricated which changes the nature of its surface plasmon in the presence of an analyte, than the presence or concentration of that analyte can be determined, and a useful sensor has been built.

The resonance angle and wavelength are detected at a distance as a minimum intensity in the reflected light. The light detector 20 is at a distance much greater than the wavelength of light, the far- field. This requires the use of a focusing lens or fiber optic. The use of the prism and the far-field detection scheme results in a complex optical design that is often temperature sensitive. This temperature sensitivity is due to changes in temperature less than 0. 1° C or an illumination angle less than 0.0001 degree affecting the angle of reflection as much as the changes in index of refraction from analyte binding.

A less temperature-sensitive method is to use gold nanostructures coated with a thin gold film to couple the light to the plasmon modes. This method has been used in a commercial system manufactured by LamdaGen, Inc. A SPR-dεtection system consistent with this method is shown in FIG. 2, Light from a light source 72 via a first optical fiber 74 is focused onto a nanoparticle film, The nanoparticle film is comprised of a glass layer 90 and a gold film 78 with polystyrene nanosphcres 80 grown by self-assembly. The polystyrene nanospheres have gold evaporated on them covering the exposed half 76. The incident illumination resonates with the conduction band electrons of the gold at a particular wavelength dependant on the nanosphere size, spacing and the index of refraction of the surrounding medium (including the analyte). The reflected light is captured and focused onto a second optical fiber 82. The second optical fiber 82 carries the collected light to a detector 84. The analyte 86, such as a protein, is bound to the surface of the nanoparticles and changes the local index of refraction. See, e.g., X. Hong and F. J. Kao, "Microsurfacc Plasmon Resonance Biosensing Based on GoId- Nanoparticle Film,'" Applied Optics 43, no. 14 (2004): 2868-2873, incorporated herein by reference, and Hiroyuki Takei, Michael Himmelhaus, and Takayuki Okamoto, "Absorption spectrum of surface-bound cap-shaped gold particles," Optics Letters 27, no. 5 (March 1 , 2002): 342-344, doi:10.l364/OL.27.000342. incorporated herein by reference. The problem with this prior art method is that it still relies on distant detection which requires bulky optics 88 and potentially only yields a reduced signal.

Another approach is to detect the plasmon resonance in the near field or within the rapidly decaying evanescent field of the plasmons. This has been done by DeVlamink et al. by fabricating gold nanoparticles onto SiO₂ directly on GaAs

detectors, as discussed m I. De Vlaminck el al,, "Local Electrical Detection of Single Nanoparticle Plasmon Resonance,^"1' JSo no I ett 1 , no. 3 (2007;: 703-706, incorporated herein by reference, and U.S. Patent Application Serial No. 20090027681 , incorporated herein by reference, DcVlaminck's method removes the contribution of the incident light from the plasmon resonance detection by using a pair of detectors, one with a nanoparticle and one without. The problem with this method is thai the incident light can overwhelm the signal, resulting m a less sensitive system. DeVlammck et al. suggest the use of a continuous film of gold m combination with nanoscalc semiconductor photodctectors. In the likely e\ent of larger detectors (e.g., a few microns m width) they suggest the use of additional topological nano features in the gold film, such as grooves or indentations. This is based upon the well studied method of enhanced transmission through gold films with nanoscalc holes. C. Genet and 1. W. Ebbesen. "Light m tiny holes," Nature 445, no. 7123 (January 4, 2007): 39-46. dυi:l 0.1038/naiure05350. incorporated herein by reference,

An embodiment of the invention includes a device comprising a plurality of nanoparticlcs and a noble metal film comprising a first side and a second side, the

plurality of nanoparticlcs being located on the second side of said metal film, The device also includes a binding sample contacting the second side of said metal film and a light- sensitive, semiconductor detector array located at a distance less than 200 nanometers from the first side of the metal film. Optionally, the noble metal film comprises gold, silver, copper, or platinum,

Optionally, the semiconductor detector array comprises a GaAs detector array, an InGaAs detector array, a Si detector array, or a HgCaTe detector array.

Optionally, the nanoparticlcs comprise one of noble-mctal-eoated nanoparticles and noble metal nanoparticlcs. Optionally, the noblc-mctal-coated nanoparticles comprise gold-coated nanoparticles, silver-coated nanoparticles, copper-coated nanoparticles, or platinum-coated nanoparticles, and wherein the noble metal nanoparticles comprise gold nanoparticles. silver nanoparticles. copper nanoparticles. or platinum nanoparticles.

Optionally, the detector array comprises a focal plane array coupled to a readout integrated circuit.

Optionally, the device further includes a wavelength-restricted or wavelength- selectable light source operable to illuminate the binding sample. Optionally, the light source comprises a light-emitting diode, a laser diode, or a laser..

Optionally, the device further includes an insulator loeatcd between the detector array and the noble metal film.

Optionally, the binding sample comprises a biological sample or a chemical compound. Optionally, the biological sample comprises a protein.

5 Optionally, the device further includes an insulator and a semiconductor located between the light-sensitive, semiconductor detector array and the first side of the noble metal film. Optionally, the insulator comprises air and glass, and the semiconductor comprises silicon, SiOy, GaAs oxide, InGaAs oxide, or HgCa Fe oxide.

Another embodiment of the invention includes a device comprising a plurality of I O rianυparticles, and a noble metal film comprising a first side and a second side, the plurality of nanoparticles being located on the second side of the noble metal film. I he device further includes a binding sample coating said second side of said metal film, a light-sensitive, semiconductor detector array located at a distance from the first side of the noble metal film, and an insulator located between the noble metal film and the light- 15 sensitive, semiconductor detector array. 1 he insulator is optionally comprised of air, glass, a micTolcns, and/or a microchanncl plate glass. Optionally, the insulator is comprised of a semiconductor oxide.

Optionally, the noble metal film comprises gold, silver, copper, or platinum.

Optionally, the semiconductor detector array comprises a GaAs detector array, an InGaAs detector array, a Si detector array, or a HgCaTe detector array,

Optionally, the nanoparticles comprise nobie-metal-coated nanoparticles and noble metal nanoparticles. Optionally, the noble-metal-coated nanoparticles comprise gold-coated nanoparticles, silver-coated nanoparticles, copper-coated nanoparticles, and platinum-coated nanoparticles, wherein the noble metal nanoparticles comprise gold nanoparticles, silver nanoparticles, copper nanoparticles, or platinum nanoparticles.

Optionally, the detector array comprises a focal plane array coupled to a readout integrated circuit. Optionally the detector array comprises a standard CMOS or standard CCD imaging chip

Optionally, the device comprises a wavelength-restricted or wavelength-selectable light source operable to illuminate the binding sample, Optionally, the light source comprises a light-emitting diode, a laser diode, or a laser. Optionally, the device further includes an insulator located between the detector array and the noble metal film.

Optionally, the binding sample comprises a biological sample and a chemical compound. Optionally, the biological sample comprises a protein.

An embodiment of the invention is less temperature sensitive, more compact, more affordable and/or has a higher sensitivity than presently available alternatives in the market. For example, the embodiment does not require a prism.

FlG. 1 is a block diagram of a prior art Surface Plasmon Resonance detector using a Kretschmann Prism configuration.

FIG. 2 is a block diagram of another prior art Surface Plasmon Resonance detector. FIGs. 3a and 3b is a top view and side view, respectively, of a detector according to an embodiment of the instant invention.

FlG. 4 is a graph illustratively showing the detection of a resonance shift with a single wavelength source.

F(Gs. 5a and 5b are side views of two variations of a detector assembly according to another embodiment of the instant invention.

FIG. 6 is a graph illustrating the enhanced transmission of gold nanoparticlcs on a gold film as compared to a gold film alone. The arrow indicates thai unlike the other wavelengths in the spectrum, at ~920nm the intensity of transmitted light is greater for the gold nanoparticlc - gold film combination than gold film alone. The addition of material Increases the transmission of light. The same 60nni gold film is used in both cases.

BEST MODES OF CARRYING OUT THE INVENTION

5 An embodiment of the invention includes a device shown by way of example in

FlGs. 3a and 3b. The device comprises a plurality of nanoparticles 100 and a noble metal film 110 comprising a first side and a second side, the plurality of nanoparticles being located on the second side of said metal film. For the purposes of this specification, the phrase noble metal is defined as a non-reactive metal that has conduction band electrons

I O capable of resonating with incident illumination to generate Surface Plasmon Resonance. Examples of noble metals are copper, gold, platinum, and silver. The device also includes a binding sample 120 coating the second side of said metal film and a light- sensitive, semiconductor detector array 130 located at a distance less than 200 nanometers from the first side of the metal film.

15 The binding sample, for example, includes one or more proteins or other molecular compounds. An example of such a binding sample is an olfactory receptor protein, which can be used to bind to molecules such as certain odorants. An example of such a olfactory receptor protein is bacteriorhodopsin.

Optionally, the noble metal film comprises gold, silver, copper, or platinum. Optionally, the semiconductor detector array comprises a GaAs detector array, an InGaAs detector array, a Si detector array, or a HgCaTe detector array,

Optionally, the nanoparticles comprise one of noble-metal-coated nanopaiticles and noble metal nanoparticles. Optionally, the noblε-metal-coated nanoparticles 5 comprise gold-coated nanoparticles, silver-coated nanoparticles, copper-coated nanoparticles. or platinum-coated nanoparlicles, and wherein the noble metal nanoparticles comprise gold nanoparticles, silver nanoparticles, copper nanoparticles, or platinum nanoparticles.

Optionally, the detector array comprises a focal plane array coupled to a readout I O integrated circuit.

Optionally, the device further includes a wavelength-restricted or wavelength- selectable light source 140 operable to illuminate the binding sample. Optionally, the light source comprises a light-emitting diode, a laser diode, or a laser.

Optionally, the device further includes an insulator 150 located between the 15 detector array and the noble metal film.

Optionally, the binding sample comprises a biological sample or a chemical compound, Optionally, the biological sample comprises a protein.

Optionally, the device further includes an insulator and a semiconductor located between the light-sensitive, semiconductor detector array and the first side of the noble metal film. Optionally, the insulator comprises air and glass, and the semiconductor comprises silicon, SiO₂, GaAs oxide, InGaAs oxide, or MgCaTe oxide, A layer of oxide or other insulating material between the detector and the noble metal film may be needed to tune the resonance wavelength or insulate the detector array from the noble metal film.

5 Sec, e.g., I. De Vlaminck et al., "Local Electrical Detection of Single Nanoparticle Plasmon Resonance,'" Nano Lett 7, no. 3 (2007): 703-706, incorporated herein by reference.

Applicant determined that the opaque nature of a noble metal film would allow removal of the contribution of the incident illumination to the plasmon resonance

I O detection, A light source illuminates the elements of die semiconductor detector array, but is not required to cover a large range of wavelengths. For example, the range of wavelengths is a single band/wavelength. Alternatively, the band is preferably IOnm or less. More than 1 OOnm for a band would likely diminish the signal from a change in the index of refraction to zero. The shift in resonant peaks observed with substance binding

15 is, for example, detected as a decrease or increase in signal intensity at a particular pair of wavelengths, such as shown by way of illustration in FIG. 4. By extension, the signal intensity shift is optionally detected by observing multiple wavelengths simultaneously as is shown in the spectrum in FIG. 4.

Another embodiment of the invention, shown by way of example, in FIGs. 5a and 5b , includes a device comprising a plurality of nanoparticles 100, and a noble metal film 1 10 comprising a first side and a second side, the plurality of nanoparticles being located on the second side of the noble metal film. The device further includes a binding sample 120 coating said second side of said metal film, a light-sensitive, semiconductor detector array 130 located at a distance from the first side of the noble metal film, and an insulator located between the noble metal film and the light-sensitive, semiconductor detector array. The insulator comprises air, glass, a microlens 150 (shown in FIG. 5a), and/or a microchannel plate glass 160 (shown in FIG. 5b). Examples of illustrative insulators are found in U.S. Patent No. 4,695,719 to Wilwerding, incorporated herein by reference.

Optionally, the noble metal film comprises gold, silver, copper, or platinum.

Optionally, the nanoparticles comprise noble-metal-coated nanoparticles and noble metal nanoparticles. Optionally, the noble-metal-coated nanoparticles comprise gold-coated nanoparticles, silver-coated nanoparticles, copper-coated nanoparticles, and platinum-coated nanoparticles, wherein the noble metal nanoparticles comprise gold nanoparticles, silver nanoparticles, copper nanoparticles, or platinum nanoparticles.

Optionally, the device comprises a wavelength-restricted or wavelength-selectable light source operable to illuminate the binding sample. Optionally, the light source comprises a light-emitting diodc,,a laser diode or, a laser,

Optionally, the device further includes an insulator located between the detector array and the noble metal film.

Optionally, the binding sample comprises a biological sample and a chemical compound. Optionally, the biological sample comprises a protein. Another embodiment of the invention is implemented, for example, as an olfactory protein binding sensor. In this embodiment, the semiconductor detector array is implemented using a focal plane detector array and Read-Out integrated circuit f "RQIC"). The focal plane detector array and the ROIC are used to detect plasmom generated from nano structural changes in the o [factor)_' receptor complex that occur with odorant binding. The olfactory receptors will be in a complex with G-protcins. a lipid membrane and gold nanoparticles. Odorants revcrsibly bind to the olfactory receptors and change the mass and nariostructure of the complex. This change in mass results in a plasmon generated in the gold nanoparticles. The plasmon is detected as a decrease in light measured by a photodiodc of the focal plane detector array. The change in pholodiodc currents within the array is read out by the ROIC and an image of the response of the array of sensors is captured, A decrease in pixel intensity indicates binding of an odorant at the sensor corresponding to that pixel.

Obviously, many modifications and variations of the present invention are possible in light of the above teachings without departing from the true scope and spirit of the invention. It is therefore to be understood that the scope of the invention should be determined by referring to the following appended claims.

Claims

What is claimed is:

1. A device comprising: a plurality of nanoparticles; a nobic metal film comprising a first side and a second side, said plurality of nanoparticles being located on said second side of said metal film; a binding sample contacting said second side of said metal film; and a light-sensitive, semiconductor detector array located at a distance less than 200 nanometers from said first side of said metal film.

2. The device according to claim 1, wherein said metal film comprises one of gold, silver, copper, and platinum.

3. The device according to claim 1, wherem said semiconductor detector array comprises one of a GaAs detector array, an InGaAs detector array, a Si detector array, and a

HgCaTe detector array,

4. The device according to claim 1 , wherein said nanoparticles comprise one of noble- metal-coated nanoparticles and noble metal nanoparticles.

5. The device according to claim 4, wherein said noblc-mctal-coatcd nanopariicies comprise one of gold-coated nanopariicies, silver-coaled nanoparticles, copper-coated nanoparticles, and platinum-coated nanoparticles, wherein said noble metal nanoparticles comprise one of gold nanoparticles, silver 5 nanoparticles, copper nanoparticles, and platinum nanopariicies.

6. The device according to claim 1, wherein said detector array comprises a focal plane array coupled to a readout integrated circuit.

I O 7. The device according to claim 1, further comprising a wavelength-selectable light source operable to illuminate said binding sample.

8. The device according to claim 7, wherein said light source comprises one of a light- emitting diode, a laser diode, and a laser.

15

9. The device according to claim 1, further comprising an insulator located between said detector arrav and said noble metal film.

10, The device according Io claim 1, wherein said binding sample comprises one of a biological sample and a chemical compound.

11 , The device according to claim i 0, wherein said biological sample comprises a protein,

12, The device according to claim 1 , further comprising one of an insulator and a semiconductor located between said light-sensitive, semiconductor detector array and said first side of said metal film.

13, The device according to claim 12, wherein said insulator comprises one of air and glass, and said semiconductor comprises one of silicon, SiO2, GaAs oxide, InGaAs oxide, and HgCaTe oxide.

14. A device comprising: a plurality of nanoparticles; a noble metal film comprising a first side and a second side, said plurality of nanoparticles being located on said second side of said metal film; a binding sample contacting said second side of said metal film; a light-sensitive, semiconductor detector array located at a distance from said first side of said metal film; and an insulator located between said noble metal film and light-sensitive,

5 semiconductor detector array, wherein said insulator comprises at least one of air, glass, a microlens, and a rnicrochannel plate glass.

15. The device according to claim 14, wherein said metal film comprises one of gold, silver, copper, and platinum.

I O

16. The device according to claim 14, wherein said semiconductor detector array comprises one of a GaAs detector array, an InGaAs detector array, a Si detector array, and a MgCaTe detector array.

15 17, The device according to claim 14, wherein said nanoparticles comprise one of noble- mctal-coatcd nanoparticles and noble metal nanoparticles.

18, The device according Io claim 17, wherein said nob Ie -metal-coated nanoparticlcs comprise one of gold-coated nanoparticles, silver-coaled riariopariides, copper-coated πanopartielεs, and platinum-coated nanoparticles, wherein said noble metal nanopartides comprise one of gold nanoparticlcs, silver 5 nanoparticlcs, copper nanoparticlcs, and platinum nanoparticlcs.

19. The device according to claim 14, wherein said detector array comprises a focal plane array coupled to a readout integrated circuit.

I O 20. The device according to claim 14, further comprising a light source operable to illuminate said binding sample.

21. The device according to daim20, wherein said light source comprises one of a Ught- eraitting diode, a laser diode, and a laser.

15

22. The device according to claim 14, further comprising an insulator located between said detector array and said noble metal film.

23, The device according Io claim 14, wherein said binding sample comprises one of a biological sample and a chemical compound.

24, The device according to claim 23, wherein said biological sample comprises a protein,