Biofunctionalization of PDMS-based microfluidic systems

Abstract

Three simple approaches for the selective immobilization of biomolecules on the surface of poly(dimethylsiloxane) (PDMS) microfluidic systems that do not require any specific instrumentation, are described and compared. They are based in the introduction of hydroxyl groups on the PDMS surface by direct adsorption of either polyethylene glycol (PEG) or polyvinyl alcohol (PVA) as well as by a liquid-based oxidation step. The hydroxyl groups are then silanized using a silane containing an aldehyde end-group that allows the surface to interact with a primary amine moiety of the biomolecule structure to be immobilized. The entire process takes 4.5h. The required steps can be characterized in less than 15 hours by contact angle measurements, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The performance of the biofunctionalization process can be assessed by using peroxidase enzyme as a model biomolecule. Its correct immobilization and stability is easily tested by developing an analytical approach for hydrogen peroxide (H2O2) detection in the biofunctionalized microfluidic system and carrying out analytical measurements for a period of up to two months.