Hydroxyapatite coating of poly(2-hydroxyethyl methacrylate) hydrogel by biomimetic method

The recently proposed biomimetic method has been performed on samples of poly(2-hydroxyethyl methacrylate) p(HEMA) hydrogel in order to improve their interface with bone. Following the biomimetic process it was possible to obtain a bioactive hydroxyapatite coating on the p(HEMA) substrates. FTIR analysis showed that characteristic peaks of p(HEMA) progressively disappear, owing to the formation of a surface coating. In fact new peaks appear corresponding to the ones of P-O stretching (1116 and 1035 cm(-1)) and P-O bending (580 cm(-1)) vibration modes, thus suggesting that the method is effective in promoting the formation of a surface phosphate layer. The formation of hydroxyapatite crystals is confirmed by SEM and EDS results. The adhesive strength was measured and turned out to be higher than the one reported for PMMA substrate. The experimental results suggest that, as reported in the literature for other supports, the silicate ions released from the glass in the first stage bind themselves to the polymeric support. (C) 1999 Kluwer Academic Publishers