Research Of Optofluidic Biosensor Based On Fabry-Perot Cavity

Optofluidic biosensors based on refractive index detection technology have received extensive attention due to its label-free detection, real-time results, high sensitivity, anti-electromagnetic interference, low detection limit, etc. Currently optofluidic biosensor mainly include Surface Plasmon Resonance (SPR) type, Whispering Gallery Mode (WGM) resonator type, Fabry-Perot resonator type, optical fiber grating type, in which only SPR achieves industrialization and have vast applications in biomedical research, environmental monitoring, health and other fields. Fabry-Perot cavity optofluidic biosensor is suitable for both volume detection (living cell) and surface detection, and it is one of the hot spots in recent years.All glass optofluidic biosensor based on Fabry-Perot cavity with high Q value was designed and fabricated, and the measurement system with low system noise based on optical differential detection and phase lock-in detection technology was also designed. The all glass sandwich structure can completely eliminate the etching roughness of the channel surface, and can extend the operating wavelength to visible and ultraviolet regions compared with that of Si-based sensor. The quality-factor of the FPC channel is 875 with the cavity length is 170μm, and the system noise can be reduced to 1.2 nV by combining optical differential detection with phase lock-in detection. A detection limit of 15ng/mL for glucose solution, which corresponds to a refractive index unit of 2.0×10-9, was experimentally demonstrated. This ultra-low detection limit is the minimum detection limit as we known, compared with conventional SPR sensors with that of 10-6～10-8 RIU.An optical Fabry-Perot cavity biosensor containing agarose hydrogel was proposed and designed, and the measurement of the adsorption effect of the bovine serum albumin (BSA) has been experimentally demonstrated, which extends the application range of the optical Fabry-Perot cavity biosensor.