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

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