The processing and characterization of animal-derived bone to yield materials with biomedical applications. Part II: milled bone powders, reprecipitated hydroxyapatite and the potential uses of these materials

Further studies on the processing and use of animal-bone-derived calcium ph osphate materials in biomedical applications are presented. Bone powders so urced either from the direct crushing and milling of bovine, ovine and cerv ine bone or after being subjected to defatting and acid digestion/NaOH repr ecipitation and sodium hypochlorite hydrogen peroxide treatment of animal b ones were characterized using Fourier transform infra-red (FTIR) spectrosco py, C-13 solid state magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy, atomic absorption (AA) and inductively coupled plasma ( ICP) spectrometric techniques. Bone powders were trialled for their potenti al use as a substrate for phosphine coupling and enzyme immobilization as w ell as a feedstock powder for plasma spraying on titanium metal substrates. Results indicated that enzyme immobilization by phosphine coupling could b e successfully achieved on milled cervine bone with the immobilized enzyme retaining some activity. It was found that the presence of impurities norma lly carried down with the processing of the bone materials (viz., fat and c ollagen) played an important role in influencing the adsorbency and reactiv ity of the powders. Plasma spraying studies using reprecipitated bovine-der ived powders produced highly adherent coatings on titanium metal, the compo sition of which was mostly hydroxyapatite (Ca-10(PO4)(6)(OH)(2)) with low l evels of alpha-tricalcium phosphate (alpha-Ca-3(PO4)(2)) and tetracalcium p hosphate (Ca4P2O9) also detected. In general, animal derived calcium phosph ate materials constitute a potentially cheaper source of calcium phosphate materials for biomedical applications and make use of a largely under-utili zed resource from abattoir wastes. (C) 2000 Kluwer Academic Publishers.