Single-Step Oxidative Chemical Vapor Deposition of -COOH Functional Conducting Copolymer and Immobilization of Biomolecule for Sensor Application

A platform for fabrication of conductive copolymer based resistive biosensor on nonconductive substrate is demonstrated. The -COOH functional groups in the copolymer of thiophene-3-acetic acid (TAA) and 3,4-ethylenedioxythiophene (EDOT) was employed for immobilization of a biomolecule. The sheet resistance of the conductive copolymer thin films significantly increased upon immobilization of the biomolecule. In terms of the fabrication method, application of bromine as an oxidant in this oxidative chemical vapor deposition (oCVD) technique considerably improved the conductivity of the copolymer and also notably reduced the polymer synthesis steps. This low temperature oCVD process shows promises for coating any substrate, for example, paper, plastics, silicon and glass with highly conducting, conformal polymeric films for the future applications in fabricating flexible biosensor devices.