PDMS-based microstructured biosensor

Abstract

In this paper, we introduce an alternative fabrication method to build a Polydimethylsiloxane (PDMS) waveguide system for bio-sensing applications. The sensor is based on the fact that the refractive index (RI) of PDMS can be manipulated by changing the ratio between the base and the curing agent, as well as the curing temperature. We further increase the RI difference between the core and cladding by adding a microstructure in the cladding. The microstructure is a periodic array of holes that can be filled with a liquid (each hole is 500 μm in diameter). The holes have the effect of decreasing the effective refractive index (eRI) of the cladding and thus helping the confinement of an electromagnetic wave in the core. As a fluid fill the holes the eRI of the cladding increases and thus the wave confinement is reduced.