PLASMA DEPOSITION OF ULTRATHIN FILMS OF POLY(2-HYDROXYETHYL METHACRYLATE) - SURFACE-ANALYSIS AND PROTEIN ADSORPTION MEASUREMENTS

A method for the preparation of ultrathin films of poly(2-hydroxyethyl methacrylate) (PHEMA) by simultaneous condensation and RF plasma depo sition of 2-hydroxyethyl methacrylate (HEMA) is described. Interaction s of proteins with plasma-deposited and model PHEMA surfaces (spin-cas t PHEMA, radiation-grafted PHEMA, and bulk PHEMA gels) were examined. Films prepared by conventional plasma deposition (i.e., without enhanc ing HEMA condensation by substrate temperature reduction) were also st udied. I-125-radiolabeled fibrinogen was used to study the protein ads orption and retention characteristics of these materials. Kinetic prot ein adsorption and free iodide uptake studies were performed. In addit ion, gravimetric analysis, X-ray photoelectron spectroscopy, static se condary ion mass spectrometry, and water contact angle measurements we re made to compare physical and chemical properties of the various hyd rogel specimens and to gain insight into the reasons for their differe nt protein interactions. Results demonstrate that plasma deposition of HEMA on substrates at low substrate temperatures is a viable method f or preparing ultrathin, hydrogel films for biomedical applications.