Monolayer Detection of Biochemical Agents Using Etched-Core Fiber Bragg Grating Sensors

It is demonstrated that the etched-core fiber Bragg grating sensor can be used to detect down to a monolayer of biological and chemical agents immobilized on the surface of the fiber. Theoretical models based on calculating the effective index of the surrounding medium in the presence of immobilized layer(s) were developed and confirmed experimentally by immobilizing a monolayer of 3-aminopropyl-monoethoxydimethyl-silane (APMDS) and polymers of 3-aminopropyl-triethoxysilane (APTES) on the surface of the fiber. The immobilization of APMDS and APTES is confirmed by carrying out hybridization of DNA. We also demonstrate that the sensor can be used to understand and optimize biological and chemical processes.