| Despite the distinct advantages of poly(dimethylsiloxane) (PDMS) for biomedical applications, because of its
hydrophobic nature, suffers from non-specific protein adsorption and platelet adhesion and activation when used
as a blood-contacting material. To confer hydrophilicity and biomolecules repelling characteristics, well-defined
and high-density poly(2-hydroxyethyl methacrylate) (PHEMA) brushes are synthesized via surface-initiated
atom transfer radical polymerization (SI-ATRP) on the PDMS substrate. First, PDMS surface is activated using an
ultraviolet/ozone (UVO) wet treatment in water media to introduce hydroxy moieties without scarifying the
surface property resulting a crack-free SiO2 surface. Then, 3-(2-bromoisobutyramido)propyl(trimethoxy)silane
(BrTMOS), the active ATRP initiator, is immobilized on the UVO-treated PDMS surface to prepare a thin layer of
hydrophilic PHEMA brush on PDMS substrate exhibiting excellent protein and platelet resistance. PHEMA
brushes supply a biomimetic feature by combining antifouling properties due to hydrophilic characteristic with
bioactive properties resulted from the presence of a high density hydroxy groups, which are subsequently used
for biomolecules conjugation. The results indicate that grafting of PHEMA chains on the PDMS surface enhances
the surface wettability which leads to a decrease in non-specific protein adsorption and platelet adhesion
compared to the bare PDMS substrate. The adhered platelets on the PHEMA-tethered PDMS substrate maintain
their normal round morphology. Furthermore, the conjugated gelatin macromolecules onto the tethered PHEMA
chains promote the adherence and growth of human umbilical vein endothelial cells via ligand-receptor interactions. |