REAGENTLESS SENSORS WAVEGUIDE GRATING COUPLING SENSORS MACH-ZEHNDER INTERFEROMETER SENSORS SURFACE PLASMON RESONANCE SENSORS

Transcription

1 REAGENTLESS SENSORS WAVEGUIDE GRATING COUPLING SENSORS MACH-ZEHNDER INTERFEROMETER SENSORS SURFACE PLASMON RESONANCE SENSORS

2 Reagentless Grating Coupler Sensor Angle, θ, is related to the analyte refractive index n superstrate (n eff ) p = sin(θ)n superstrate + λm/λ

3 Reagentless Grating Coupler Sensor Prism coupling condition p i sin(θ) = p g k i sin(θ) = k g 2πsin(θ)/λ i = 2π /λ g sin(θ) /c i = /c g [c = λ] sin(θ)n i /c o = n g /c o sin(θ)n i = n g [c = c o n] Grating coupling condition sin(θ)n i + λm/λ = n g n i n g refractive index of the superstrate (incident beam) effective refractive index of the guide

4 Reagentless Grating Coupler Sensor Angle, θ, is related to the antibody-analyte complex refractive index if the analyte is large: n (physiological saline) ~1.333

5 Reagentless Grating Coupler Sensor Angle, θ, is related to the antibody-analyte complex refractive index if the analyte is large: n (physiological saline) ~1.333 n (protein) ~1.5

6 Reagentless Grating Coupler Sensor Angle, θ, is related to the antibody-analyte complex refractive index if the analyte is large: A plot of coupling angle against analyte concentration gives a calibration curve against which unknown analyte concentrations can be determined

7 SOL-GEL SILICA THIN FILM FABRICATION after Lukosz and colleagues Dip coat or spin coat a film of tetraethoxysilane in a volatile solvent onto a substrate Low temperature thermally cure to give a soft silica film 4 Emboss with master gating High temperature cure to give a hard silica film with an embossed grating

8 Grating Coupling Immunosensor Calibration Curve for the Heat Shock Protein HSP70 MicroVacuum OWLS Sensors, Hungary

9 MACH-ZEHNDER INTERFEROMETER If both arms of the above integrated optical waveguide are identical the inputted light will split and then recombine constructively.

10 MACH-ZEHNDER INTERFEROMETER The propagation velocity in the wave guide depends on the superstrate refractive index

11 Propagation velocity in the wave guide = 2πk o ʋn eff n eff = function of n superstrate, n core and n substrate Superstrate, e.g. air, analyte solution Waveguide, e.g. metal phosphate glass Substrate, e.g. glass, silica n superstrate n core n substrate

12 2 x, core ko neff ) p ( k n 2 o core with similar terms for: and 2 x, core ko neff ) p ( k n 2 x, substrate ko neff ) p o 2 core ( k n 2 x, prism ko neff ) p o o ( k n 2 substrate 2 prism

13 MACH-ZEHNDER INTERFEROMETER The propagation velocity in the wave guide depends on the superstrate refractive index When the superstrate is the different over the arms of the Mach-Zehnder sensor there is destructive interference on leaving the arms

14 MACH-ZEHNDER INTERFEROMETER An immunosensor can be fabricated by immobilising an antibody on both arms of an integrated planar optical waveguide Mach-Zehnder interferometer

15 MACH-ZEHNDER INTERFEROMETER Binding a large analyte, e.g. protein, to only ONE arm of the sensor changes the superstrate refractive over that arm and leads to destructive recombination. The resultant change in the observed intensity of the output light can be related to the analyte concentration

16 INTEGRATED OPTICAL DEVICES CAN NOW BE FABRICATED IN INEXPENSIVE MATERIALS, e.g. ELECTRON MICROGRAPH OF ETCHED STRIPE WAVEGUIDES IN A FERRIC PHOSPHATE SPIN-COATED GLASS THIN FILM

17 Mach-Zehnder Interferometer for detection of Listeria monocytogenes Normalised Power Intensity versus microbe concentration Sarkar D1, Gunda NS, Jamal I, Mitra SK. Biomed Microdevices Aug;16(4):509-20

18 Mach-Zehnder Interferometer for detection of Listeria monocytogenes Phase change versus microbe concentration Sarkar D1, Gunda NS, Jamal I, Mitra SK. Biomed Microdevices Aug;16(4):509-20

19 Mach-Zehnder Interferometer for detection of Listeria monocytogenes Illustration of Selectivity Sarkar D1, Gunda NS, Jamal I, Mitra SK. Biomed Microdevices Aug;16(4):509-20

20 SURFACE PLASMON RESONANCE Prism Coupling (Kretschmann arrangement) Grating Coupling

21 SURFACE PLASMON RESONANCE INCIDENT LIGHT BEAM DIELECTRIC e.g. GLASS or PLASTIC DIELECTRIC e.g. AIR THIN METAL FILM e.g. GOLD or SILVER Thickness less than wavelength of the exciting light, typiclaly 60 nm

22 SPR INCIDENT LIGHT BEAM REFLECTED LIGHT BEAM DIELECTRIC e.g. GLASS or PLASTIC METAL e.g. GOLD or SILVER DIELECTRIC e.g. AIR

23 SPR INCIDENT LIGHT BEAM REFLECTED LIGHT BEAM DIELECTRIC e.g. GLASS or PLASTIC METAL e.g. GOLD or SILVER DIELECTRIC e.g. AIR

24 SPR INCIDENT LIGHT BEAM REFLECTED LIGHT BEAM DIELECTRIC e.g. GLASS or PLASTIC METAL e.g. GOLD or SILVER DIELECTRIC e.g. AIR

25 SPR INCIDENT LIGHT BEAM REFLECTED LIGHT BEAM DIELECTRIC e.g. GLASS or PLASTIC METAL e.g. GOLD or SILVER DIELECTRIC e.g. AIR

26 SPR INCIDENT LIGHT BEAM REFLECTED LIGHT BEAM DIELECTRIC e.g. GLASS or PLASTIC METAL e.g. GOLD or SILVER DIELECTRIC e.g. AIR

27 SURFACE PLASMON RESONANCE INCIDENT LIGHT BEAM DIELECTRIC e.g. GLASS or PLASTIC EVANESCENT FIELD THIN METAL FILM e.g. GOLD or SILVER Thickness less than wavelength of the exciting light, typiclaly 60 nm DIELECTRIC e.g. AIR

28 SPR INCIDENT LIGHT BEAM NO REFLECTED LIGHT BEAM DIELECTRIC e.g. GLASS or PLASTIC METAL e.g. GOLD or SILVER DIELECTRIC e.g. AIR

29 SPR INCIDENT LIGHT BEAM NO REFLECTED LIGHT BEAM DIELECTRIC e.g. GLASS or PLASTIC METAL e.g. GOLD or SILVER DIELECTRIC e.g. AIR

30 SPR INCIDENT LIGHT BEAM NO REFLECTED LIGHT BEAM DIELECTRIC e.g. GLASS or PLASTIC METAL e.g. GOLD or SILVER DIELECTRIC e.g. AIR

31 SPR INCIDENT LIGHT BEAM NO REFLECTED LIGHT BEAM DIELECTRIC e.g. GLASS or PLASTIC METAL e.g. GOLD or SILVER DIELECTRIC e.g. AIR

32 SPR INCIDENT LIGHT BEAM NO REFLECTED LIGHT BEAM DIELECTRIC e.g. GLASS or PLASTIC METAL e.g. GOLD or SILVER DIELECTRIC e.g. AIR

33 SURFACE PLASMON RESONANCE TRANSVERSE ELECTRIC (TE) MODE (s-polarised) TRANSVERSE MAGNETIC (TM) MODE (p-polarised) E incident H incident X x H reflected X E reflected Hincident E incident x E incident H reflected Region 1 k incident θ r k reflected θ o z Region 1 k incident θ r k reflected θ o z Region m θ t k transmitted Region m θ t k transmitted X H transmitted E reflected H reflected E transmitted For SPR incident light must be p-polarised (TM)

34 SURFACE PLASMON RESONANCE INCIDENT WHITE LIGHT REFLECTED LIGHT Wavevector of the surface plasmon SUBSTRATE (PRISM), n substrate METAL FILM, n metal k spr = 2 n n 2 metal 2 metal n 2 p 2 p + n 1/ 2 ANALYTE SOLUTION, n p Component of the wavevector of the incident light In the plane of the metal k l 2 n = substrate sin( ) Surface plasmon generated when k l = k spr

35 SURFACE PLASMON RESONANCE INCIDENT WHITE LIGHT REFLECTED LIGHT Wavevector of the surface plasmon SUBSTRATE (PRISM), n substrate METAL FILM, n metal k spr = 2 n n 2 metal 2 metal n 2 p 2 p + n 1/ 2 ANALYTE SOLUTION, n p Component of the wavevector of the incident light In the plane of the metal k l 2 n = substrate sin( ) Surface plasmon generated when k l = k spr

36 CONFIRMATION OF THE SURFACE PLASMON RESONANCE EQUATIONS USING LANGMUIR-BLODGETT FILMS

37 LANGMUIR-BLODGETT FILMS

38 Langmuir-Blodgett Trough Prof. Vitaly J. Vodyanoy, Institute for Biological Detection Systems, Auburn

39

40 SOLID SUPPORT

41 LANGMUIR-BLODGETT FILMS

42 SURFACE PLASMON RESONANCE

43 SURFACE PLASMON RESONANCE (SPR) IMMUNOSENSORS

44 SURFACE PLASMON RESONANCE ANALYTE SOLUTION METAL SURFACE PLASMON WAVE AT THIS SURFACE Water n = ~1.333 EVANESCENT FIELD ENERGY Protein n = ~1.5

45 SURFACE PLASMON RESONANCE INCIDENT WHITE LIGHT REFLECTED LIGHT Wavevector of the surface plasmon SUBSTRATE (PRISM), n substrate METAL FILM, n metal k spr = 2 n n 2 metal 2 metal n 2 p 2 p + n 1/ 2 ANALYTE SOLUTION, n p Component of the wavevector of the incident light In the plane of the metal k l 2 n = substrate sin( ) Surface plasmon generated when k l = k spr

46 SURFACE PLASMON RESONANCE ANALYTE SOLUTION Capture antibody (IgG) Serum albumin METAL SUBSTRATE θ SALINE SALINE + CAPTURE ANTIBODY SALINE + CAPTURE ANTIBODY + BOUND ANTIGEN REFLECTED LIGHT INCIDENT ANGLE,θ (degrees) 82

47 SURFACE PLASMON RESONANCE

48 SURFACE PLASMON RESONANCE Rough surface terms Smooth surface term

49 SURFACE PLASMON RESONANCE Prism Coupling (Kretschmann arrangement) Grating Coupling

50 SURFACE PLASMON RESONANCE n metal n p k o sin(θ) n substrate + 2πm/Λ k spr = 2 n n 2 metal 2 metal n 2 p 2 p + n 1/ 2

51 AIR METAL FILM e.g. GOLD SUBSTRATE e.g. GLASS THICK METAL FILM Coupled Surface Plasmon Waves Sharper resonance Better sensor sensitivity THIN METAL FILM

52 Sharper resonance -> More accurate sensor

53 Sharper resonance -> More accurate sensor Noise added

54 Kyeong-Seok Lee et al, Sensors 2010, 10,

55 42 nm Ag / 131 nm ZnS-SiO2 / 16 nm Au Kyeong-Seok Lee et al, Sensors 2010, 10,

56 Non-specific binding Non-specific binding of analyte Non-specific binding of serum proteins Specific binding Analyte Red blood cell Sensor surface If the sensor depends on a refractive index (n) change, eg SPR, the specifically bound analyte, non-specifically bound analyte, nonspecifically bound serum proteins and any cells settling on the sensor surface produce a response, eg shift in SPR resonance

57 Non-specific binding Non-specific binding of analyte Non-specific binding of serum proteins Specific binding Analyte Red blood cell Label Sensor surface Non-specific binding present in labelled assays but far less important than in reagentless sensors

58 Coupled SPR Modes Very Strong Evanescent Field Highly Sensitive Fluorescence Based Immunosensor

59 Highly Sensitive Fluorescence Based Immunosensor

60 Enhancement of Immunoassay s Fluorescence and Detection Sensitivity Using Three-Dimensional Plasmonic Nano-Antenna-Dots Array Liangcheng Zhou, Fei Ding, Hao Chen, Wei Ding, Weihua Zhang, and Stephen Y. Chou, Analytical Chemistry, 2012, 84,

61 Enhancement of Immunoassay s Fluorescence and Detection Sensitivity Using Three-Dimensional Plasmonic Nano-Antenna-Dots Array Liangcheng Zhou, Fei Ding, Hao Chen, Wei Ding, Weihua Zhang, and Stephen Y. Chou, Analytical Chemistry, 2012, 84,

62 Enhancement of Immunoassay s Fluorescence and Detection Sensitivity Using Three-Dimensional Plasmonic Nano-Antenna-Dots Array Liangcheng Zhou, Fei Ding, Hao Chen, Wei Ding, Weihua Zhang, and Stephen Y. Chou, Analytical Chemistry, 2012, 84,

63 SURFACE PLASMON RESONANCE Prism Light does not pass through the sample (+) Metal thickness has to be tightly controlled (-) Grating Light does passes through the sample (-) Metal thickness does not effect resonance (+) Both Non-specific binding (-) Solution refractive index (-)

64 Biacore SPR equipment

65 Texas Instruments SPR sensor