P(AAM-CO-EG) INTERPENETRATING POLYMER NETWORKS GRAFTED TO OXIDE SURFACES - SURFACE CHARACTERIZATION, PROTEIN ADSORPTION, AND CELL DETACHMENT STUDIES

We investigated the composition, properties, and utility of a novel co polymer of P(AAm-co-EG) designed to be an adaptable, durable, and bioc ompatible surface treatment of metallic, polymeric, and ceramic materi als. Solution deposition and photoinitiation reactions were employed t o graft, a silane layer and then two sequential polymer layers(a disco ntinuous two stage polymerization) onto oxide surfaces. Different solv ents, polymer concentrations, and cross-linker concentrations in the t op polymer layer were compared. Contact angle measurements, spectrosco pic ellipsometry, and X-ray photoelectron spectroscopy were used to ch aracterize layer wettability, thickness, and chemistry, respectively A sandwich type network formed between acrylamide and poly(ethylene gly col) when acetone was used as the solvent for both layers. In contrast , an interpenetrating polymer network between acrylamide and poly(ethy lene glycol) formed when acetone and methanol were used as the solvent s for polymerization of the acrylamide and poly(ethylene glycol) layer s, respectively. Interpenetrating polymer network configured samples w ere tested for protein adsorption and strength of cell attachment. Pro tein adsorption experiments in 15% fetal bovine serum indicated that s ignificant amounts of protein do not adsorb to the surface of the thin polymer films (similar to 20 nm). Cell detachment experiments indicat ed that cells contacting copolymer-modified surfaces were removed by l ower shear stresses than cells contacting clean and amine-terminated, (N-(2-aminoethyl)-3-aminopropyl)-trimethoxysilane modified surfaces.