Composites based on hydroxyapatite and natural biopolymers are promising materials for bone grafting. In this work, samples of hydroxyapatite were synthesized by chemical precipitation from aqueous solutions in the presence of high molecular weight hyaluronic acid (0,4-0,8 wt.%). The resulting powders are represented by carbonate-containing nanohydroxyapatite and contain 89-98 wt.% of polysaccharide. A correlation has been established between the content of hyaluronic acid in the mother solution and the crystal chemical, structural and morphological characteristics of the samples. It was revealed that, in comparison with the hydroxyapatite sample, in viscoelastic media of the polysaccharide, powders are formed that have a smaller parameter a of the hydroxyapatite crystal lattice, close in value to the stoichiometric phase. With an increase in the content of hyaluronic acid in the mother solution, the crystallinity, crystallite sizes and specific surface area of the composites decrease; their average value is 16 nm and 47 m2/g. Samples based on nanohydroxyapatite and polysaccharide consist of oval-lamellar agglomerated particles. At the maximum content of hyaluronic acid in the model solution, amorphized round conglomerates, dense in structure, are formed. The synthesized composites can be used in medical practice as osteoconductive implants, as well as to create nanoencapsulated drug delivery systems.

The effects of high- molecular hyaluronic acid on the phase composition, crystal lattice parameters, and the sizes of the regions of coherent dispersion, depending on its content in the synthesis solution, have been studied. All composites are represented by poorly crystallized carbonate hydroxyapatite. With an increase in the viscosity of the medium, the broadening of the parameter a of the hydroxyapatite crystal lattice decreases and the most crystallized precipitates are formed, the average size of the crystallites is similar to 15 nm, the specific surface area of the samples does not change (105-130 m(2)/g).

CarbonateCarbonates-containing hydroxyapatiteHydroxyapatite has been synthesized from prototype humanHuman synovial fluid in the presence of prolineProline and glycineGlycine. The resultant powders have revealed to contain 61–71 wt

— Carbonate-containing hydroxyapatite has been synthesized from prototype human synovial fluid in the presence of proline. The resultant powders have been shown to contain 61 to 71 wt % the amino acid. The presence of proline in the model solution has been shown to change the crystallinity and specific surface area of the samples, without influencing the composition or crystallite size of the solid phase. High amino acid concentrations lead to the formation of poorly crystallized composites consisting of smaller nanocrystals. The dissolution of the samples in a 0.9% NaCl solution and an acetate buffer has been shown to be a two-step process. The highest solubility in weakly acidic solutions has been demonstrated by the precipitates containing the amino acid.

Carbonate-containing hydroxyapatite has been synthesized from prototype human synovial fluid in the presence of glycine. The resultant powders have been shown to contain 75 to 80 wt % the amino acid. If the model solution contains less than 0.08 mol/L of glycine, the latter influences neither the composition of the solid phase nor the size of the forming crystallites, but changes the degree of their crystallinity and the specific surface area of the material. At high amino acid concentrations, we observe the formation of poorly crystallized composites consisting of smaller nanocrystallites. The dissolution of the samples in a 0.9% NaCl solution has been shown to be a two-step process. The highest solubility under weakly acidic conditions has been demonstrated by the precipitates containing the largest amount of the amino acid.

The results of the study of the composition, morphology, microhardness of human bone tissue in the "norm" and in pathology are presented. It is shown that the processes occurring in the affected bone tissue are characterized by a decrease in the crystallinity of the mineral component, compaction and degradation of the bone substance, conversion of collagen and a low molecular weight organic component.

Based on prototype human synovial fluid by varying the content of sodium ions and calcium ions in model solution synthesized calcium phosphate containing hydroxyapatite oktakaltsy whitlokite phosphate. It is shown that increasing the concentration of sodium cations leads to the formation of phases mostly represented vitlokite. The kinetic laws dissolving samples in acetate buffer, depending on their phase composition and the content of sodium ions in the mother liquor model.

Using prototype human synovial fluid, we have synthesized a calcium phosphate nanopowder consisting of two crystalline phases (whitlockite and carbonate-containing hydroxyapatite). The nanopowder was used to produce calcium phosphate (monetite) coatings on titanium substrates by microarc oxidation. It has been shown that, with increasing microarc oxidation voltage (from 200 to 300 V), the mass, thickness, roughness parameter, and Ca : P ratio of the coatings increase linearly. Increasing the voltage to 300 V and the calcium phosphate coating growth time to 10 min allows a single-phase coating up to 100 μm in thickness, consisting of monetite nanocrystals, to be produced on a metallic surface and its adhesion strength to be improved.

This work examined the protein composition of organic components for different organo-mineral aggregate in the bone tissue of healthy people (without bone disease) and patients with coxarthrosis (arthrosis of the coxofemoral joint), urinary, dental, and salivary calculi. The content of the water-soluble organic substances with a peptide bond in urinary stones depends on the mineral composition of the sample. When monohydrate calcium oxalate crystallizes in the solution in the presence of glutamic acid, the crystal growth is stabilized. When the concentration of amino acid grows, the inhibitory effect grows. Other amino acids (lysine, glycine, aspartic acid) have an inhibitory effect on hydroxyapatite crystal growth in the range of the tested concentrations. By an increase in the electrostatic interaction with non-stoichiometric hydroxyapatite, the tested amino acids can be ranked in order as: lysine > glycine > glutamic acid > aspartic acid. In the course of bone arthrosis, the molecular weight of the organic content was observed to be less than that of collagen. Close packing of the deformed collagen fibers was one of the causes of the increased hardness of arthritic bones. The amino acid composition in the bone tissue of men and women in the age range of 30-79 to 60 years does not depend on the age and gender identity of the samples. After 60 years, the amino acid content varies by age and gender.

Synthesized mixture of calcium phosphates of the model solution articular synovial fluid. Based on suspensions of the compound by the method of micro-arc oxidation coating produced on the surface of the titanium alloy VT1-0. The resulting coating improved bioactivity and osteoinductive properties of the surface layer of titanium. It is noted that the voltage variation micro process and the application time allows to obtain a coating on the surface of titanium of different thicknesses and different roughness.

A comparative study of the microand macroelement composition of bone tissue in man "normal" with the contents of elements in the sample due to damaged bone coxarthrosis and in physiogenic (dentin and enamel) and pathogenic (saliva, dental and renal stones) biominerals. It is shown that in the "normal" bone mineral composition closest to dentin and dental calculus. It is found that in human bone tissue at coxarthrosis changed value of the atomic ratio Ca/P and the content of elements such as copper, tin, iron, manganese, strontium and chromium (in some cases). The correlation between the concentration of trace elements series Zn > Sr > Fe diseased bone with rows of dental and kidney stones.

With the use of HPLC technique, studies on the amino acid composition of human bone tissue within the age range of 30-79 years were performed. Gender-features concerning the qualitative and quantitative amino acid content have been revealed. It is demonstrated that the clinical course of coxarthrosis does not lead to significant changes in amino acid composition of human bone tissue.

Results of research of human bone fabric by methods of the X-ray diffraction, IR-spectroscopy, electronic paramagnetic resonance, high performance liquid chromatography and mass spectroscopy with the with inductively coupled plasma are presented. It has been shown that the processes occurring in the bone at coxarthrosis are characterized by reduction of crystallinity and orderliness of structure apatite. It has been revealed that coxarthrosis leads to collagen change, the structure and the general content of amino acids are preserved constants. Variations of amino acid composition of human bones are given depending on age and sex.