Abstract

Creating environmentally friendly materials with useful properties is one of the key problems of today. Particularly in-demand are specialized biocompatible materials for applications emerging in the recent years — cell and tissue engineering associated with the development of equivalents for skin and hard tissue. Polyhydroxyalkanoates (PHAs), linear polyesters of microbiological origin, are among the most promising materials developed and studied with respect to these problems. The aim of this work was to study the ability of PHA-based products to maintain the proliferation of bone marrow cells and induce reparative osteogenesis in vivo. We used highly purified PHA samples produced at the Institute of Biophysics SB RAS and in the SFU Laboratory of New Biomaterials: a homopolymer of 3-hydroxybutyric acid (P3HB) and a copolymer of 3-hydroxybutyric and 4-hydroxybutyric acid (P3HB/4HB). Using the methods of modern material science, a series of products was obtained in the form of: cell carriers, molded plates, and filling material. A comparison was made of the surface properties of the designed polymeric cell carriers; the total porosity and water absorption were estimated. The strength characteristics of the samples were studied using an Instron 5565,5 KN electromechanical universal testing system. On the example of multipotent mesenchymal stem cells (MMSCs) of rats, the ability of carriers to support the growth and division of cultured cells was demonstrated. The conditions for differentiation of MMSCs into osteoblastic series cells were studied. The differentiation of MMSCs was confirmed by the activity of alkaline phosphatase and gene expression of osteopontin. The osteoplastic properties of poly-3-hydroxybutyrate were studied using the model of a bone defect at the bottom wall of an eye-socket and the model of chronic osteomyelitis in laboratory animals. It was proved that the application of the tested biocompatible polymer material leads to a less severe inflammatory response to the implant and earlier restoration of the bone structure of the eye-socket bottom wall as compared to a cartilage allograft. It was established that filling the infected bone defects of long tubular bones after surgical treatment with a hydrophobic filling material helps to suppress the infection, provides a faster recovery of bone defects and early recovery of supporting properties of the operated limb. Thus, the possibility was demonstrated to apply biocompatible and biodegradable polymers of hydroxybutyric acid in reconstructive surgery of bone tissue.