L. F. Sukhodub

Formation of Solution-derived Hydroxyapatite Coatings on Titanium Alloy in the Presence of Magnetron-sputtered Alumina Bond Coats.

Hydroxyapatite Ca10(PO4)6(OH)2 (HAp) and calcium phosphate ceramic materials and coatings are widely used in medicine and dentistry because of their ability to enhance the tissue response to implant surfaces and promote bone ingrowth and osseoconduction processes. The deposition conditions have a great influence on the structure and biofunctionality of calcium phosphate coatings. Corrosion processes and poor adhesion to substrate material reduce the lifetime of implants with calcium phosphate coatings. The research has focused on the development of advanced methods to deposit double-layered ceramic oxide/calcium phosphate coatings by a hybrid technique of magnetron sputtering and thermal methods. The thermal method can promote the crystallization and the formation of HAp coatings on titanium alloy Ti6Al4V substrates at low temperature, based on the principle that the solubility of HAp in aqueous solutions decreases with increasing substrate temperature. By this method, hydroxyapatite directly coated the substrate without precipitation in the initial solution. Using a thermal substrate method, calcium phosphate coatings were prepared at substrate temperatures of 100-105 oC. The coated metallic implant surfaces with ceramic bond coats and calcium phosphate layers combine the excellent mechanical properties of metals with the chemical stability of ceramic materials. The corrosion test results show that the ceramic oxide (alumina) coatings and the double-layered alumina-calcium phosphate coatings improve the corrosion resistance compared with uncoated Ti6Al4V and single-layered Ti6Al4V/calcium phosphate substrates. In addition, the double-layered alumina/hydroxyapatite coatings demonstrate the best biocompatibility during in vitro tests.

The influence of ultrasound and microwave irradiation on the crystal structure of hydroxyapatite during synthesis

The paper describes the influence of ultrasound (US) and microwave (MW) irradiation on the formation of hydroxyapatite (HAP). HAP was synthesized under the imposition of these two factors of different power and without irradiation in order to compare its influence on the derived compounds structural features.

Microelements dynamics during post-fracture mineralization in hyperglycaemic condition

The aim of the current paper was to study the post-fracture mineralization dynamics in hyperglycaemic and normal conditions. It demonstrates that the hyperglycaemic state induced by alloxan inhibits osteoblast maturation and prolongs period of calcium phosphate deposition to the fracture site. The obtained data illustrates the agreeable and parallel dynamics of temporal ALP changes in normal and hyperglycaemic states with much higher enzyme activity in treatment group.