Design, Fabrication, and Testing of a Chitosan Based Optical Biosensor
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This work presents the design, fabrication, and testing of an original concept for an optical biosensor device intended for use in a microfluidic network. The device uses planar waveguides intersecting a microfludic channel with biofunctionalized patterned sidewalls to detect biomolecules via fluorescent labeling. The optical-biological interface is provided through chitosan, a natural biopolymer. Chitosan is electrodepositable, and this material platform was developed to enable spatially selective and temporally selective assembly of biospecies in the sensor using electrical signals. The unique fabrication process flow integrates waveguides and microfluidic channels which are fabricated in a single step with a thick polymer layer on a Pyrex substrate. Key to the success of the device was the development of a process to pattern indium tin oxide on the sidewalls of deep (130 um) fluid channels. The device was tested in several modes of operation and the proof of concept was shown.