Functionalized nano interdigitated electrodes arrays on polymer with integrated microfluidics for direct bio-affinity sensing using impedimetric measurement

This paper presents a fully integrated nano interdigitated electrodes array (nIDA) and microfluidic system on polymer substrate. It can be used as a miniaturized, sensitive, and easy-to-use impedimetric sensor for genomics, proteomics, and cellular analysis. The benefits gained from a nanoscale IDA is very high sensitivity for monitoring protein binding behavior. With the intention of integrating this nano biosensor into a lab-on-a-chip device, a gold nIDA has been successfully patterned on polymer (cyclic olefin copolymer, COC) substrate, which has been widely used for disposable lab-on-a-chip applications. The fabricated device has been characterized in deionized (DI) water and different concentrations of KCl salt solution ranging from 10−1 to 10−5 M using electrochemical impedimetric spectroscopy (EIS). Experimental and theoretical impedance responses are well matched. The preliminary test shows that the impedance from the same buffer solution increases after protein binding (mouse monoclonal anti-rabbit immunoglobulin, IgG) at the gold electrode surface and the impedance change is directly related to the IgG concentration. These results support the feasibility of applying the proposed device as a sensitive protein immunosensor on a disposable polymer substrate.