Real Time Flow-Through Biosensor

An all polymeric platform based on planar microring resonator employing a microfluidic flow-through approach is presented and exploited for biosensing applications. A micromilled hole in the center of the microring resonator drives the analyte flow towards the sensing surface, so optimizing the transport kinetic. A simulated and experimental evaluation of the improved performances in terms of kinetic transport and response time is also presented. Biosensing experiments with bovine serum albumin (BSA) based solutions at different concentrations are performed. Optical characterizations by resonance peak shift show a linear behaviour up to 200 nM and a saturation condition at higher concentrations in SU-8 based microring resonators. A reduction of more than 4 times of the response times, as compared with the standard flow-over approach, is obtained with the proposed flow-through approach. The proposed sensing architecture, allowing the single addressing of ring resonator, gives numerous advantages related to time responses and multiplexing of different analytes for a label-free biosensing.