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The critical sensor: a new type of evanescent wave immunosensor
E F Schipper1, R P Kooyman, A Borreman
1MESA Research Institute, Department of Applied Physics, University of Twente, AE Enschede, The Netherlands.
Biosensors & Bioelectronics
|January 1, 1996
Summary
A novel planar waveguide immunosensor was developed, offering a sensitive method for detecting adlayer growth. This critical sensor achieves high sensitivity comparable to existing technologies but with simpler fabrication and no metal layer requirement.
Area of Science:
- Optoelectronics
- Biosensing
- Surface Chemistry
Background:
- Surface adsorption changes refractive index, a phenomenon utilized in optical sensors.
- Existing sensors like surface plasmon resonance (SPR) and grating couplers have limitations in fabrication or material requirements.
Purpose of the Study:
- To develop a new planar waveguide immunosensor based on critical angle shifts.
- To evaluate the sensor's sensitivity and compare it with established technologies.
- To highlight the advantages of the new sensor regarding fabrication and material usage.
Main Methods:
- Development of a planar waveguide structure for sensing.
- Utilizing the principle of critical angle shift due to refractive index changes upon analyte adsorption.
- Experimental validation of the sensor's performance through immunosensing experiments.
Main Results:
- The sensor measures changes in refractive index contrast caused by surface adsorption.
- A lower detection limit of 2 x 10(-2) nm in adlayer growth (12 pg/mm2 analyte coverage) was achieved.
- Sensitivity is comparable to surface plasmon resonance and grating coupler sensors.
Conclusions:
- The developed planar waveguide immunosensor is a viable alternative for sensitive analyte detection.
- The sensor offers advantages in ease of fabrication, adjustment, and does not require a metal layer.
- This technology presents a promising platform for various immunosensing applications.