11 November 2005 A label-free optical waveguide biosensor with sub-wavelength gratings
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Proceedings Volume 6007, Smart Medical and Biomedical Sensor Technology III; 600712 (2005) https://doi.org/10.1117/12.630610
Event: Optics East 2005, 2005, Boston, MA, United States
In this paper, the reflection resonance spectrum of a sub-wavelength diffraction grating-coupled waveguide is used to analyze biomolecular interactions in real time. When the diffraction grating waveguide structure is destroyed by external factors such as slight refractive index changes of the buffer or molecule adsorption on the grating surface, the optical path of the light coupled through the grating into the waveguide is changed and a resonance wavelength shift is induced as a result. By detecting this resonance wavelength shift, the optical waveguide biosensor provides the ability to identify the kinetics of the biomolecular interaction on an on-line basis without the need for the extrinsic labeling of the biomolecules. A theoretical analysis of the sub-wavelength optical waveguide biosensor is performed. A biosensor with a narrow reflection resonance spectrum, and hence an enhanced detection resolution, is then designed and fabricated. Currently, the detection limit of the optical waveguide sensor is found to be approximately 10-5 refractive index units. The developed biosensor is successfully applied to study the kinetics of an antibody interaction with protein G adsorbed on the sensing surface.
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Jenq-Nan Yih, Yen-Chieh Mao, Yi-Ming Chu, Wei-Han Wang, Lai-Sheng Chen, Fan-Ching Chien, Kuang-Li Lee, Pei-Kuan Wei, Shean-Jen Chen, "A label-free optical waveguide biosensor with sub-wavelength gratings", Proc. SPIE 6007, Smart Medical and Biomedical Sensor Technology III, 600712 (11 November 2005); doi: 10.1117/12.630610; https://doi.org/10.1117/12.630610

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