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Attaching Biological Probes to Silica Optical Biosensors Using Silane Coupling Agents
Published on: May 1, 2012
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A size selective porous silicon grating-coupled Bloch surface and sub-surface wave biosensor.
Gilberto A Rodriguez1, Judson D Ryckman, Yang Jiao
1Department of Electrical Engineering and Computer Science, Vanderbilt University, VU Station B #351824, 2301 Vanderbilt Place, Nashville, TN 37235-1824, United States.
Biosensors & Bioelectronics
|November 12, 2013
Summary
This study introduces a novel porous silicon biosensor that uses Bloch surface waves (BSW) and sub-surface waves (BSSW) to selectively detect molecules by size. This new technology offers significantly enhanced sensitivity for both large and small analytes.
Area of Science:
- Nanotechnology
- Biosensing
- Surface Physics
Background:
- Biosensors are crucial for detecting analytes, but often struggle with size selectivity and sensitivity.
- Porous silicon (PSi) offers a versatile platform for optical sensing applications.
- Bloch Surface Waves (BSW) and sub-surface waves (BSSW) are surface-bound optical modes with potential for enhanced sensing.
Purpose of the Study:
- To demonstrate a novel grating-coupled porous silicon biosensor utilizing both BSW and BSSW modes.
- To achieve size-selective detection of both large and small molecules.
- To enhance the sensitivity of biosensing compared to existing porous silicon technologies.
Main Methods:
- Fabrication of a porous silicon grating structure.
- Theoretical analysis using dispersion relations and simulated refractive index shifts.
- Experimental verification using small chemical molecules and a large DNA oligonucleotide.
- Benchmarking against current porous silicon sensing technologies.
Main Results:
- Demonstrated size-selective detection of large (DNA) and small (chemical) molecules.
- BSW mode effectively sensed immobilized large analytes at the surface.
- BSSW mode provided sensitive detection of small molecules confined near the surface.
- Achieved a 6-fold increase in sensitivity for large molecules and 33% for small molecules compared to existing PSi technology.
Conclusions:
- The developed porous silicon grating-coupled BSW/BSSW biosensor enables precise, size-selective molecular detection.
- This technology represents a significant advancement in biosensing sensitivity and selectivity.
- This work reports the first grating-coupled BSW biosensor and the first BSSW propagating mode for biosensing applications.
