EVALUATION OF BIOPHYSICAL PROPERTIES OF THE BONE TISSUE FOR BIOMEDICAL APPLICATIONS

Background and aim: The volume of reconstructive surgery in traumatology in recent decades has increased significantly due to an increase in traumas, numbers of affected in local military conflicts, and environmental deterioration. This has led to an increase in demand for plastic materials, and the need to create modern high technologies to meet this need, including alternative sources of bone implants. Any solution to this problem would involve an in-depth study of bone biophysical properties with innovative techniques to develop requirements to elaboration of new effective implants based on natural bone, as well as on natural or synthetic analogues. This study aimed exactly at these aspects. Materials and methods: We studied human bone samples taken from various parts of the skeleton aged from 3 to 89 years and animal (bovine) bone samples aged from 1.5 to 2 years. Biophysical characteristics of the studied materials were assessed at the stage of sample preparation with original author's methods of physical and mechanical processing, in the process of analysis of patterns of normal changes in the bone structure and function, as well as during changes in its composition with age, anisotropy of the material and the level of structural organization. Structure patterns were studied by classical (light, scanning electron microscopy) and advanced (acoustic microscopy) techniques. Methods of engineering biomechanics were used to assess functional changes in macro and micro volumes of bone samples. Results: The main study results involve the development of innovative methods of sample preparation and structural and functional analysis. First of all, these are the methods of mechanical processing of bone fragments based on the use of hollow cylindrical milling cutters in the environment of limited amounts of mineralized biological tissues, as well as on the application of hydrodynamic cutting ensuring a delicate and highly efficient bone cut. Another distinctive feature of the study is the elaborated methodology for morphological and mechanical analysis of bone samples at the macro and micro levels, with consideration of real physical and chemical condition of samples. To ensure sample sterility, the authors proposed innovative techniques using of ozone-oxygen mixtures. The study results gave a  complex of quantitative characteristics describing age-related compositional changes of the human bone, anisotropy of its physical and mechanical characteristics, osteon parameters and physical and mechanical characteristics of bone tissue depending on its composition. Conclusion: The use of the proposed methodology allowed for obtaining of new data on biophysical properties of bone tissue that are of interest for bioimplantology, biomaterial science and expands basic information on the bone as a natural biocomposite. They can be the basis for development of practical guidelines on optimization of the choice of bone fragments for manufacture of implants based on the detected patterns of changes in macro- and microstructure, physical and mechanical characteristics and bone composition in the studied age range.

bone tissue, physical and mechanical characteristics, bioimplant, methods of sample preparation, hollow cylindrical milling cutters, hydrodynamic cutting of biologic tissues