Characterization of protein-resistant dextran monolayers.

A range of synthetic thiolated dextrans of varying molecular weights and degrees of thiol substitution have been investigated as well-defined monolayer coatings for the reduction of nonspecific protein adsorption. Atomic force microscopy and surface plasmon resonance (SPR) analysis revealed that the surface coverage of the dextran monolayers increased with an increasing degree of thiol substitution, but conversely decreased with increasing molecular weight. SPR was then employed to monitor bovine serum albumin protein adsorption to thiolated dextran monolayers from a flowing buffered solution. Whilst a significant reduction of protein adsorption to a thiolated dextran layer coated surface compared to an uncoated surface was observed, the degree of conversion of hydroxyls to thiol groups and molecular weight was shown to affect the protein-resistant performance of the dextran layer.