A New Approach for Selective Surface Functionalization of Carbon Electrodes in Biosensing by Plasma Direct-Writing

摘要

Carbon electrodes fabricated by Carbon Microelectromechanical systems (C-MEMS) process is known to be chemically inert. Hence, surface functionalization is required for their use as biosensors and electrochemical electrodes. Surface functionalization of carbon electrodes is conventionally performed by oxygen plasma treatment or acid treatments. These methods generally affect the whole surface of electrodes and cannot limit functionalization to only at specific locations on the electrodes. This paper introduces a novel plasma direct-writing technique for selective functionalization of carbon electrodes with carboxylic groups at room temperature and atmospheric pressure. We demonstrated the plasma direct-writing by patterning oxygen functional groups on carbon electrodes derived from pyrolysis of photolithographically patterned photoresist. The resulting surface chemistry is investigated by scanning electron microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDS). Functionalization of hydroxyl and carboxyl groups is a first step towards immobilization of DNA or immunoglobulin for carbon based biosensors. Our plasma direct-writing technique not only enables controlled writing of functional groups but also enables control over the degree of functionalization in a simple one step procedure.