Controllable Nonspecific Protein Adsorption by Charged Hyperbranched Polyglycerol Thin Films

Antifouling thin films derived from charged hyperbranched polyglycerol (hbPG) layers were fabricated and evaluated. The anionic hbPG (a-hbPG) monolayers and cationic hbPG/anionic hbPG (c/a-hbPG) bilayers were adsorbed on the underlying self-assembled monolayers (SAMs) of cysteamine and 3-mercaptopropionic acid (3-MPA) by electrostatic interaction, respectively, and their procession was monitored by surface plasmon resonance spectroscopy (SPR). The adsorption of bovine serum albumin (BSA) and fibrinogen on the premade a-hbPG and c/a-hbPG thin films was measured and the capability of these thin films to resist nonspecific protein adsorption was evaluated by SPR as well. It is observed that the c/a-hbPG bilayer films possessed good antifouling properties. With c/a-hbPG bilayers consisting of higher molecular weight a-hbPG, the adsorption of BSA and fibrinogen were as low as 0.015 ng/mm(-2) and 0.0076 ng/mm(-2), respectively, comparable to the traditionally ultralow antifouling surfaces (<0.05 ng/mm(-2) of nonspecific protein adsorption). This work proved that the charged hbPG thin films can strongly reduce the nonspecific protein adsorption and have the promise for the antifouling coatings with improved performance.