Synthesis and physicochemical and biological studies of crystalline calcium phosphates substituted with various ions

The main goal of this project is to develop novel crystalline calcium phosphates enriched with a variety of ions of potential biomedical importance. Another primary goal of the project is to develop two- and multiphase materials with different ion release characteristics. Basic research carried out under the project: Synthesis of various crystalline calcium phosphates (hydroxyapatite (HA), calcium orthophosphates (βTCP and αTCP) of calcium hydrogen phosphates (anhydrous CaHPO4 (DCPA) and dihydrate CaHPO4 ∙ 2H2O (DCPD)) containing admixtures of "foreign" ions: cations I, II or III-valued (e.g. K +, Ag +, Zn2 +, Mn2 +, Mg2 +, Cu2 +, Ga3 +) and various anions (e.g. SeO3 2-, SeO4 2-, SiO4 4-, BO3 3-). chemical composition of the obtained substituted calcium phosphate materials and physicochemical studies of these materials Planned research methods: X-ray powder diffraction (PXRD), mid-infrared spectroscopy (FT-IR), Raman (R) spectroscopy, solid state nuclear magnetic resonance spectroscopy (ssNMR), atomic absorption spectrometry (ASA), wave dispersive X-ray fluorescence (WD XRF) and excited plasma emission spectrometry (ICP OES). Analysis of ion release from the obtained materials (ICP MS plasma excitation mass spectrometry method). Development of two- and multiphase materials based on the obtained substituted calcium-phosphate materials with different rates of foreign ion release. Assessment of biological properties of the obtained materials. Reasons for undertaking the research topic: Calcium phosphates are a group of inorganic materials of significant importance in implantology, regenerative medicine and dentistry. In mineralized human tissues (i.e. bones, enamel, dentin or tooth cement), the inorganic building material that provides them with hardness is the so-called biological apatite, i.e. nanocrystalline carbonate hydroxyapatite containing many different ionic substitutions. Therefore, synthetic bone replacement materials, metallic implant coatings, endosteal cements or dental materials often contain calcium phosphates, which ensure biocompatibility, bioactivity and low cytotoxicity. For many years, the most popular among synthetic calcium phosphates, hydroxyapatite (HA) with the total formula Ca10 (PO4) 6 (OH) 2, and at the same time the least resorbable, is effectively doped with various ions in order to enrich it with additional biological, physicochemical or mechanical properties. On the other hand, very little is known about the possibility of ionic substitutions in other crystalline calcium phosphates, e.g. calcium orthophosphate Ca3 (PO4) 2 (βTCP and αTCP form), crystalline anhydrous calcium hydrogen phosphate CaHPO4 (DCP) and calcium hydrogen phosphate dihydrate CaHPO4 ∙ 2H2O (DCP∙ 2H2O) ). Few studies on the enrichment of βTCP and αTCP show that such materials are characterized by better solubility and faster release of foreign ions than substituted apatites. Currently, in medicine, two-phase materials (most often containing pure, unsubstituted HA and βTCP in various proportions) are used, which ensure better bioactivity and easier osseointegration. The development of new substituted calcium phosphates, planned in our project, is aimed at broadening the knowledge in the field of ion exchange in selected crystalline calcium phosphates. We want to develop materials with different resorbability and ion release rates. We expect that the results of the research planned by us will be particularly important for the progress of biology, medicine and materials engineering (designing bone substitute materials).