XPS characterisation of biocompatible hydroxyapatite-polymer coatings

Hydroxyapatite coatings on polymeric substrates have been prepared by treating samples of poly(methyl methacrylate) (PMMA) and poly(2-hydroxyethyl methacrylate) with a biomimetic method and by producing a mechanical mixture of polymers (PMMA and poly(butylmethyl methacrylate) and hydroxyapatite (1:1). The surface chemical composition of the samples has been studied by using X-ray photoelectron spectroscopy. Both the reference polymers and the hydroxyapatite coatings have been analyzed. The surface modifications induced by interaction of the coatings with osteoblast cells have been studied as a function of the exposure time, after in vitro treatment for 7, 15 and 21 days. Quantitative XPS analysis enabled us to compare the quality of the samples and the different response to the in vitro treatment.