Polydimethyl siloxane microfluidic channel protein functionalization techniques

Abstract

The most commonly used polymer in microfluidic device fabrication is polydimethylsiloxane (PDMS). Many applications require the functionalization of the surface of PDMS with proteins (e.g. antibodies) which prompted the evaluation of a variety of techniques that have been developed to bind proteins to the surface. such as non-specific binding, protein passive adsorption and activation with Glutaraldehyde cross-linking, or with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride) (EDC) cross linkers. It has been shown that using EDC crosslinker after APTES activation results in more than double the protein bonding strength to the PDMS surface than the bonding strength that results from passive/non-specific adsorption. The contribution of PDMS curing conditions on protein adsorption to its surface was also studied, and showed that increased curing time is the factor that reduces passive adsorption the most. Finally, we have shown that reaction time between the protein and surface has a direct relationship with bond strength and that initial protein concentration in solution was only an effective factor when the protein was at low concentrations…