Surface modification with both phosphorylcholine and stearyl groups to adjust hydrophilicity and hydrophobicity

A new monolayer film with tunable hydrophilicity and hydrophobicity was constructed on glass coverslips by stepwise grafting with both phosphorylcholine (PC) and stearyl groups. The glass coverslips were firstly hydroxylized to provide reactive sites on the surfaces. Subsequently, chlorodimethyl-n-octadecylsilane was chemically adsorbed onto the surface to impart the required hydrophobicity. The remaining hydroxyl groups were grafted with 1,6-diisocyanatohexane. Finally, 2-hydroxy-2-ethylphosphorylcholine was grafted onto the attached isocyanate groups. Dynamic contact angle (DCA) measurement and X-ray photoelectron spectroscopy (XPS) analysis confirmed that the step-by-step modification process was successful. The adsorption of bovine serum albumin and bovine plasma fibrinogen, as well as the adhesion and aggregation of platelets were suppressed with the introduction of phospholipid moieties on the surfaces. This tunable surface may have potential applications in the fields of separation science, tissue engineering, cytobiology, drug delivery and gene therapy.