α-tricalcium (α-TCP) phosphate is widely used as an osteoinductive biocompatible material, serving as an alternative to synthetic porous bone materials. The objective of this study is to obtain a highly filled fibrous nonwoven material composed of poly-3-hydroxybutyrate (PHB) and α-TCP and to investigate the morphology, structure, and properties of the composite obtained by the electrospinning method (ES). The addition of α-TCP had a significant effect on the supramolecular structure of the material, allowing it to control the crystallinity of the material, which was accompanied by changes in mechanical properties, FTIR spectra, and XRD curves. The obtained results open the way to the creation of new osteoconductive materials with a controlled release of the source of calcium into the living organism.

Two variants of gene-activated hydrogels based on sodium alginate containing plasmid DNA with the gene of vascular endothelial growth factor (VEGF-A) are developed. The former represented alginate hydrogel without additional components; the latter contained up to 25 wt % of octacalcium phosphate (OCP) micrograins. Alginate-based hydrogels without OCP are characterized by a honeycomb structure with the pore size of 50–200 μm and mechanical compression strength of 0.2 MPa. Addition of OCP micrograins results in filling of the polymer framework by them and an increase in the compression strength to 0.57 MPa at 16.7 wt % of OCP with a decrease to 0.49 MPa with an increase in the OCP content to 20 wt %. Both variants of gene-activated hydrogels induce reparative myogenesis in the central zone of muscle defect; a larger number of MyoG⁺ cells and newly formed MyH7B⁺ muscle fibers are identified as compared to analogous hydrogels without plasmid DNA after two weeks after surgery (p < 0.05).

This work is aimed at developing homogeneous, uniformly distributed fine-crystalline coatings based on triclinic octacalcium phosphate pentahydrate (OCP, Ca₈H₂(PO₄)₆⋅5H₂O) on the surface of ceramic substrates made of hydroxyapatite (HA, Ca₁₀(PO₄)₆(OH)₂). The process of the crystalline layer of low-temperature calcium phosphates consists in a partial dissolution and recrystallization of surface layers of ceramic substrates through the intermediate phase of dicalcium phosphate dihydrate (DCPD, CaHPO₄⋅2H₂O). A buffer solution having an increased concentration of \({{{\text{H}}}_{{\text{2}}}}{\text{PO}}_{4}^{ + }\) and \({\text{HPO}}_{4}^{{2 + }}\) anions and containing Ca²⁺ ions is proposed for surface modification. When creating the crystalline coating, the buffer solution partly dissolves the surface layers, and the coating with the required phase composition and morphology is formed upon reaching the necessary concentration of Ca²⁺ ions on the solution–ceramic interface. To obtain a uniform coating, Ca²⁺ ions are gradually added to the buffer solution. The conditions of the beginning of the dissolution of calcium phosphate ceramic substrates and the thermodynamic conditions of the formation of uniform OCP-based coatings are established.

Optimization of the reparative regeneration of striated skeletal muscle tissue is actual for clinical practice. Volumetric muscle loss usually heals through the fibrous scar formation. Herein, there are numerous of methods under developed focused on reparative myogenesis induction. One of the promising approaches in this area is formed by gene-activated materials, particularly, in the hydrogel form. We developed a gene-activated hydrogel based on hyaluronic acid and plasmid DNA with the gene of vascular endothelial growth factor A (VEGF-A). Firstly, we showed a biocompatibility of the product in the subcutaneous test in mice. Using marker plasmid DNA carrying the luciferase gene, prolonged delivery of gene constructs to cells in vivo with a peak in transgene expression at day 7 was confirmed, while the same plasmid DNA in an aqueous solution provided a maximum level of delivery at day 1. Being implanted into a volumetric defect of the anterior tibial muscle in rats the gene-activated hydrogel activated angiogenesis in 2 weeks after surgery and induced MYH7B+-muscle fibers formation in the central zone of the defect at average number 50,0±16,1 and 21,8±10,5 in 2 and 4 weeks, respectively, whereas a hydrogel without plasmid DNA did not have any myogenic effects. Thus, plasmid DNA with VEGFA in the sodium alginate-based hydrogel induced angiogenesis in the volumetric muscle loss model and stimulated reparative myogenesis that could be used for further development of products effective for treatment of patients with muscle pathology.

Data obtained by the authors upon creating composite materials based on biopolymers and calcium phosphates adapted to the prototyping technology are presented. Results concerning the creation and investigation of the properties of three-dimensional structures for the replacement of bone defects, as well as novel studies of the functionalization of three-dimensional prototypes based on calcium phosphates and a biopolymer, namely, modification of the surface of mineral–polymer materials by the biomimetic application of active calcium phosphates, are shown.

There is a strong unmet need for bone grafts and substitutes combining osteoinductive capacities and biophysical properties for using them in minimally invasive surgical interventions. We have developed three variants of injectable gene-activated bone substitutes containing three components: octacalcium phosphate microgranules (OCP), plasmid DNA delivering the gene of vascular endothelial growth factor, and one of the hydrogels based on sodium alginate, type I collagen, and hyaluronic acid. The molecules of the gene constructs were contained both in the hydrogel and on the surface of the OCP microgranules. In the model of a critical-sized bone defect in rabbit parietal bone, we found that all the gene-activated hydrogels contributed to bone tissue regeneration, however, the largest amount of newly formed bone, including those in the central part of the defect, was detected in the groups with gene-activated materials based on hyaluronic acid and collagen. Thus, the developed materials can be considered as candidates for medical devices, but additional studies are required to assess the dose-depended effect and optimize the materials composition.