A new and easy surface functionalization technnology for monitoring wettability in heterogeneous nano- and microfluidic devices

Abstract

We have developed a new and easy surface functionalization technology for monitoring wettability in heterogeneous nano- and microfluidic devices. This technology is based on mussel inspired, dopamine chemistry and it permits to end-graft hydrophilic polymer brushes onto virtually any surface in a low-viscosity regime. We have successfully modified a variety of different solid surfaces, such as Si, SiO2, Ag, Cu, SU8 and PDMS. The modified surfaces were characterized by water contact angle measurements, atomic force microscopy, cyclic voltammetry and by electrokinetic measurements. The adsorption of proteins on the unmodified and modified surfaces was probed with fluorescently labeled albumin. We clearly demonstrated that the studied surfaces became non-fouling when modified with a hydrophilic, polyacrylamide brush, while they remained protein adsorbing when unmodified and/or modified with the dopamine film only. We believe that this universal surface modification approach will be extremely useful in nano- and micro-fluidic devices build from a variety of different materials.