Interface Sensitized Optical Microfiber Biosensors

Sensitivity is an important parameter to characterize the performance of sensors. Interfacial modification and functionalization is an effective strategy to improve the sensitivity of optical biosensors. This paper reports our recent development on interface sensitized fiber optic biosensors for the detection of ultra-low concentration of biological targets. We employ microfiber mode interferometer as transducer to sense the molecular binding interaction induced surrounding refractive index change. By modifying the microfiber surface to increase the assembling surface area and enhance the evanescent field energy density, ultra-low limit of detection of 1.65 × 10-15M and 6.82 × 10-17M, respectively, were realized for neurotransmitter γ-amino-butyric acid and cellular cytochrome c.