Coating of anionic phospholipid polymer onto silica-based microchannel to minimize nonspecific protein adsorption

An anionic phospholipid copolymer PMBSSi was synthesized to construct a permanent coating with protein resistant units (2-methacryloyloxyethyl phosphorylcholine, MPC) as well as surface charges onto the silica based (quartz and glass) microchannel through a one-step modification. The coating showed a high property of minimizing the non-specific adsorption of both anionic and cationic proteins to a very low extent of less than 0.05 μg /cm² on glass substrates. In addition, a significant cathodic EOF ((1.0±0.1) ×10^-4 cm²/V·s) with approximately one-half of the EOF of the uncoated microchannel was achieved in coated microchannel at neutral pH. As a conclusion, PMBSSi coating is a simple but highly effective modification for reducing nonspecific protein adsorption, and promising to be applied in electrokinetic microfluidic systems.