Water absorption and surface properties of novel poly(ethylmethacrylate) polymer systems for use in bone and cartilage repair

The surface and bulk properties of novel methacrylate polymers prepared by gelling poly(ethyl methacrylate) (PEMA) powder with different ratios of tet rahydrofurfuryl methacrylate (THFMA) and hydroxyethyl methacrylate (HEMA) m onomers were investigated. The water adsorption and desorption characterist ics of these polymers were measured in water and phosphate buffered saline (PBS). The desorption diffusion coefficients were higher than the adsorptio n coefficients in both water and PBS. Linear relationships between the equi librium mass of water taken up and the mass of water desorbed with the conc entration of HEMA in the polymer were established. Polymer surfaces were an alysed using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Surface features varied with polymer composition; during hydration only selective areas of the surface hydrated indicating a heterogeneous sur face. Contact angle data showed no trend between the different polymers ind icating that contact angles are not an acceptable method of assessing hydro phobicity/wettability of a material which does not have a homogeneous surfa ce. The effect of these bulk and surface characteristics on biological inte ractions were examined using bovine chondrocytes and human osteoblast (HOB) cell cultures. Cell attachment decreased when HEMA was present in the copo lymer. (C) 2001 Elsevier Science Ltd. All rights reserved.