Fiber-Coupled Microcavity Probe – A Novel Optical Biosensor for Near-Field Real-Time Monitoring of Biomolecular Interactions

Abstract – We report on a novel optical biosensor design for near-field sensing based on a fiber-coupled microcavity. The device operates on the bases of sensing in the evanescent near-field zone via the amplitude and phase modulation of the reflected interference patterns. The integrated probe design offers a low-cost, robust and easy-to-fabricate alternative for label-free real-time biosensing. The first generation, pre-optimization device has already demonstrated sensitivity in the range of 10-4 and 10-5 refractive index units and 40 nm per refractive index unit. We have also demonstrated the potential use of this device in specific binding assays or concentration analyses by monitoring in real-time the solution-phase self-assembly of 5 Å aminosilane monolayer from varying bulk concentration. The application of this device as a new platform for point-of-care calibration-free concentration analysis is promising