Titanium membranes and meshes are used for the repair of trauma, tumors, and hernia in dentistry and maxillofacial and abdominal surgery. But such membranes demonstrate the limited effectiveness of integration in recipients due to their bioinertness. In this study, we prepared titania oxide (by microarc oxidation) and/or HAp (by electrophoresis deposition) coatings with alginate soaking. We used annealing at 700 °C for 2.5 h for HAp crystallinity increasing with achievement of an acceptable Ca²⁺ release rate. The feedstock HAp and prepared coatings were characterized by X-ray diffraction, IR spectroscopy, electron and optical confocal microscopy, and thermal analysis, as well as the in vitro study of solubility in saline and in vivo tests with the animal model of subcutaneous implantation (with Wistar rats). Biocompatible compounds were found for all deposited coatings. We noted that the best biological response was detected for the annealed Ca-P/TiO₂ bilayer with alginate binding. In this case, the coating crystallinity was ≈40.5-50.0%. The Ca²⁺ release rate was 2.042 ± 0.058%/mm² at 168 h after immersion in saline. Thin and mature tissue capsules with minimal inflammation and vascularization were found in histological sections. We did not detect any unwanted responses around the implants, including inflammation infiltration, suppuration, bacterial infections, tissue lyses, and, finally, implant rejection. This information is expected to be useful for understanding the properties of bioactive ceramic coatings and improving the quality of medical care in dentistry and maxillofacial surgery and other applications of titanium membranes in medicine.

Low-temperature ceramics based on magnesium calcium phosphate cement are a promising resorbable material for bone tissue restoration with the possibility of functionalization. The replacement of the magnesium Mg²⁺ ion with a calcium Ca²⁺ ion at the stage of preparation of the precursor leads to the production of multiphase ceramics containing phases of brushite, monetite, and newberyite, with different dissolution rates. Multiphase ceramics leads to volumetric resorption with preservation of their geometric shape, which was confirmed by the results of an evaluation of the output of magnesium Mg²⁺ and calcium Ca²⁺ ions into the contact solution of the ceramics and the X-ray density of ceramic samples during subcutaneous implantation. The combined introduction of sodium pyrophosphate decahydrate and citric acid monohydrate as setting inhibitors neutralizes their insignificant negative effect on the physico-chemical properties of ceramics (strength, pH, porosity), determining the optimal composition. In vivo experiments with setting inhibitors in the composition of ceramics showed a different biological response, affecting the rate of resorption on par with magnesium ions. Preliminary data on biocompatibility and solubility determined magnesium-calcium phosphate ceramics containing additives that regulate setting to be a potential material for bone tissue restoration and a vector for further research, including in orthotopic implantation models.

Despite a long period of application of metal implants, carbon–carbon medical composites are also widely used for bone defect prosthesis in surgery, dentistry, and oncology. Such implants might demonstrate excellent mechanical properties, but their biocompatibility and integration efficiency into the host should be improved. As a method of enhancing, the electrophoretic deposition of fine-dispersed hydroxyapatite (HAp) on porous carbon substrates might be recommended. With electron microscopy, energy dispersion X-ray and Raman spectroscopy, and X-ray diffraction, we found that the deposition and subsequent heat post-treatment (up to the temperature of 400 °C for 1 h) did not lead to any significant phase and chemical transformations of raw non-stoichometric HAp. The Ca/P ratio was ≈1.51 in the coatings. Their non-toxicity, cyto- and biocompatibility were confirmed by in vitro and in vivo studies and no adverse reactions and side effects had been detected in the test. The proposed coating and subsequent heat treatment procedures provided improved biological responses in terms of resorption and biocompatibility had been confirmed by histological, magnetic resonance and X-ray tomographic ex vivo studies on the resected implant-containing biopsy samples from the BDF1 mouse model. The obtained results are expected to be useful for modern medical material science and clinical applications.

The rate of resorption of calcium phosphate self-hardening materials for bone regeneration can be changed by changing the phase composition. The Ca₃(PO₄)₂/CaCO₃/Ca(H₂PO₄)₂·H₂O/Na₂HPO₄·12H₂O system is important for the synthesis of self-curing bioactive materials with variable resorption rates by changing the ratios of the initial components. Cement compositions in twelve figurative points of a four-component composition diagram at a fixed content in the α-Ca₃(PO₄)₂ system were studied with XRD, FTIR, SEM, calorimetric, and volumetric methods to obtain an idea of the effect of composition on solubility in vitro and resorption in vivo. It was found that the presence of the highly resorbable phase of dicalcium phosphate dihydrate in cement and the substitution of phosphate ions with the carbonate ions of hydroxyapatite increased solubility in vitro and resorption in vivo. The obtained results confirm the possibility of changing the solubility of a final product in the Ca₃(PO₄)₂/CaCO₃/Ca(H₂PO₄)₂·H₂O/Na₂HPO₄·12H₂O system by changing the ratio of the initial components.

Background: This article describes the protocol for the purification of xenogenic bone matrix tested by a team of authors in the article «Determining the effectiveness of a xenogeneic bone matrix decellularization protocol in in vitro and in vivo studies» (the test results were described in the journal N.N. Priorov Journal of Traumatology and Orthopedics. 2023;30(4):431–443, doi: https://doi.org/10.17816/vto622849). AIM: To conduct a comparative analysis of methods of physical and chemical purification of xenogeneic spongy bone tissue by tomographic and morphological studies. MATERIALS AND METHODS: Xenogenic bovine femoral spongiosa tissue was fragmented to the size of 10×10×10 mm and treated with water, hypertonic, hypotonic, hypotonic solutions, and 3% or 6% hydrogen peroxide solution in various combinations. Deep secondary purification with organic solvents or supercritical fluid extraction was then applied, followed by 1H NMR to determine traces of reagents. The efficiency of the optimal protocol was determined by histologic and tomographic studies with calculation of the purification factor by densitometric indices. RESULTS: In accordance with the purification coefficient calculated by densitometric indicators, the intertrabecular space of bone tissue after exposure to flowing water and hypo- and hypertonic solutions followed by cleaning with a 3% H2O2 solution is not sufficiently purified; histological analysis showed the presence of 0 to 60% osteocytes for different cleaning protocols. When replaced with a 6% H2O2 solution, the purification coefficient was higher, but bone destruction was observed. Additional deep purification allows a high purification rate while preserving the structure, but when organic solvents are used, their traces are detected in the matrix; therefore, the use of supercritical fluid extraction is more effective. CONCLUSION: The sequential use of flowing water, 0.5% NaCl solution, 3% H2O2 solution followed by sc-CO2 treatment is an effective protocol for the purification of xenogeneic spongy bone tissue.