Ulianchych N. Formation the properties of calcium-phosphate ceramics for regenerative medicine

The thesis is devoted to revealing of influence of technological parameters of the treatment with organic acid solutions and silicon doping of the synthesized sediment of nonstoichiometric HAP on physicochemical and biological properties of the received CPC; creation of nanostructured composite ceramics containing components of different solubility; creation of a biocompatible antibacterial surface with silver containing HAP on titanium implants for the development of materials to be used in regenerative medicine for the bone grafting of large defects. It was found that treatment of non-stoichiometric HAP precipitate with ascorbic acid allows to obtain three-phase CPC (α-TCP, β-TCP and HAP) in the temperature range of 800-1300 °C with different phase ratios, while doping of the precipitate with silicon promotes the formation of threephase CPC in the temperature range of 800-1200 °C. Potential annealing temperatures to obtain structures more prone to resorption and with greater solubility have been determined. Modification of the CPC with acids and silicon promotes the formation of a nanostructure, increasing the adsorption activity of modified materials almost twice. A composite nanostructured CPC consisting of spheroid nanoparticles with three-phase CPC (HAP, β-TCP, α-TCP) and needle-type β-TCP was created. This material differs from other composite CPCs in that it consists of β-TCP needle crystals obtained by chemical precipitation instead of needle-shaped HAP crystals obtained by a high-cost method. According to the results of preclinical studies of modified CPC and composite CPC, it was found that the materials optimized for technological parameters have osteoinductive properties. Antibacterial HAP coatings were obtained: by the method of microplasma spraying of silverdoped HAP and HAP coating, on which silver nanoparticles were applied by plasma dispersion in vacuum. It was found that both types of coatings have an antibacterial effect on all studied pathogenic test cultures of microorganisms. According to the results of preclinical studies of CPC and coatings on titanium implants received the Certificate of Conformity to the technical regulations №753 for medical devices in accordance with the requirements of ISO 13485, №UA.TR.039.1204, №217 from 15.09.2020, which allows using the developed materials in clinics of Ukraine. Key words: hydroxyapatite, tricalcium phosphate, solubility, adsorption activity, nanosized particles, nanopores, nanostructuring, three-phase and composite calcium-phosphate ceramics.