Value-added bioceramic materials from low-cost natural sources: their processing, characterisation and potential applications in medicine

摘要

Sources of material alternative to powders from chemical synthesis for producing bioceramic powders and biodies are described. Materials derived from low cost bone, a meat processing waste product in New Zealand have many applications in medicine. In the present study, a procedure is outlined for preparing cubic implants from excised bovine condyle cancellous bone. In this process, precut cubes are thawed, pressure-cooked in water, soaked in NaOH, microwave heated, solvent extracted in methyl acetate, soaked/ultrasonicated in NaOCl and finally dried to yield an end product that is bleached to the core, has the correct bony architecture and is cuttable to size by surgeons for use in implant applications. Mechanical measurements on the bone to quantify the effects of processing parameters predictably showed a reduction in yield stress as the bone was taken through to the final product. Earlier spectroscopic characterisation of materials produced from bone either by grinding pressure-cooked crushed bone or by acid digestion/reprecipitation revealed that the resultant powders contained residual surface organics and/or collagen, which enhanced their adsorbent properties. Studies involving uptake of drugs and a dye as well as immobilisation of trypsin using a phosphine coupling method have demonstrated the potential of the bone powders as drug delivery systems and enzyme immobilisation substrates. in addition, the reprecipitated powders have shown promise as a feedstock for plasma spraying on titanium substrates.