Calcium fructoborate coating of titanium-hydroxyapatite implants by chemisorption deposition improves implant osseointegration in the femur of New Zealand White rabbit experimental model.

BACKGROUND: The identification of biocomposites that improve cell adhesion and reduce bone integration time is a great challenge for implantology and bone reconstruction. AIM: Our aim was to evaluate a new method of chemisorption deposition (CD) for improving the biointegration of hydroxyapatite-coated titanium (HApTi) implants. CD method was used to prepare a calcium fructoborate (CaFb) coating on a HApTi (HApTiCaFb) implant followed by evaluation of histological features related to bone healing at the interface of a bioceramic material in an animal model. METHODS: The coating composition was investigated by high-performance thin-layer chromatography/mass spectrometry. The surface morphology of the coating was studied by scanning electron microscopy (SEM), before and after the in vitro study. We implanted two types of bioceramic cylinders, HApTi and HApTiCaFb, in the femur of 10 New Zealand White (NZW) rabbits. RESULTS: The release of CaFb from HApTiCaFb occurred rapidly within the first three days after phosphate-buffered saline immersion; there was then a linear release for up to 14 days. SEM analysis showed similar morphology and particle size diameter for both implants. Around the porous HApTiCaFb implant, fibrosis and inflammation were not highlighted. CONCLUSIONS: Easily applied using CD method, CaFb coatings promote HApTi implant osseointegration in the femur of NZW rabbits.

A correlation between thermodynamic properties, thermal expansion and electrical resistivity of Ag-28% Cu nanopowders processed by the mechanical alloying route.

Thermodynamic properties, thermal expansion and electrical resistivity of the Ag-28% Cu nanopowders processed by the mechanical alloying route have been investigated in the temperature range from ambient to 1048 K. The thermodynamic properties represented by the relative enthalpy, the specific heat capacity, the relative entropy and the Gibbs energy function obtained from drop calorimetric measurements have been used to reveal the occurrence of the micro-relaxation process, as well as of the correlative effects of decomposition and growth processes. On the basis of the results, the parameters that favour stable nanostructured systems in Ag-28% Cu powders synthesized by the mechanical alloying route have been identified. The correlation of the energetic parameters with thermal expansion and electrical resistivity in mechanical alloyed nanocrystalline powders with the eutectic composition is discussed.