Simulation and design of grooved fibers for fiber-optic localized plasmon resonance biosensors

Bio-molecular recognition is detected by the unique optical properties of self-assembled gold nanoparticles on the unclad portions of an optical fiber whose surfaces are modified with a receptor. To enhance the performance of the sensing platform, the sensing element is integrated with microfluidic chips to reduce sample and reagent volume, to shorten response time and analysis time, as well as to increase sensitivity. The main purpose of the present study is to design grooves on the optical fiber for FO-LPR microfluidic chip and investigate the effects of the groove geometry on the biochemical binding kinetics. The optical fiber is designed and termed as U-type or D-type based on the shape of grooves. The numerical results indicated that the design of the D-type fiber exhibits efficient performance on biochemical binding. The grooves designed on the optical fiber could also induce chaotic advection to enhance the mixing in the microchannel. The mixing patterns indicate that the D-type grooves enhance the mixing more effectively than U-type grooves. The D-type fiber with six grooves is an optimum design according to the numerical results.