Bionic mechanics of customized cellular bio-magnesium scaffolds for large-area defects of femoral shafts and implants for orthopaedics surgery

Zhao Wei-min; Li Bing-zhe; Tang Liu-ding; Peter Paul Mler

doi:10.3969/j.issn.2095-4344.2014.03.005

Abstract：BACKGROUND:In 2010, the corresponding author was supported financial y by German Academic Exchange Service, visiting the Department of Molecule Biotechnology, German Helmholtz Center of Infection Research, Braunschweig, Germany, creating the cooperation relation to research into the project“Fundament and Application of Biomimetic Technology for Customized cellular Biomagnesium Scaffolds of Loaded Tissue Engineering Bones”, finishing the present work and“Investigation on the Nanosize and Zeta(ξ)-potential of Polyelectrolytes for Biomimetic Coating Technology”. <br> OBJECTIVE:To focus on studying bionic mechanics between cellular scaffolds, customized for large area defects of femoral shafts, and new ingrown bones, as wel as bionic mechanics between host bones and platelike implants for orthopaedics surgery, by means of elastic mechanics and stereo-quantitative metal ographic analysis, and proposing the principle of bionic mechanics and the design criterion for above mentioned two types of problems, also some directions for research and development. <br> METHODS:Different types of micro-volume models for two types of composites, i.e., cellular scaffolds/new-growing bones bio-composites, as wel as plate-like implants/host bones layered composites were created, as wel as different modulus mixing rules and mechanical stresses, i.e., stimuli, were presented, respectively. <br> RESULTS AND CONCLUSION:Under the different modulus and volume fractions of scaffold materials, the mechanical stimuli of new ingrown bones are compared:(1) except cellular tantalum, the strength of cellular metal ic scaffolds/new ingrown bones composites is obviously much higher than that of original host bones, to enable resolving the problem on insufficient mechanical strengths in early period of implanting the compound between partial demineralized bone scaffolds and autogenous human bone marrow mesenchymal stem cells, as wel as other organic or inorganic scaffolds for tissue engineering. (2) The less the modulus and volume fraction of materials for cellular scaffold, the greater the mechanical stimuli of new ingrown bones wil be. For loaded tissue-engineered bones, particularly, for customized cellular scaffolds for large-area defects of femoral shaft, tibial shaft and fibular shaft, cellular bio-magnesium scaffolds wil be the best choice. The bionic mechanics between host bones and plate-like implants for orthopaedics surgery indicates:(1) the strength and rigidity of plate-like implants wil be the most important, compared with other factors, while the rise of elastic modulus wil bring about the decrease of mechanical stimuli for host bones, indistinctly, if the thickness of implant plates is little, e.g., 5 mm. (2) Nonetheless, the surface macrostructure, such as fiber networks, macro-pores, and bionic(biomimetic) coating, decreasing the elastic modulus of surface structure, wil be necessary to local y decrease stress shield effects and ensure the mechanical stimuli of host bones, to improve the bio-compatibility of implants surface and enhance the effect of biological fixation.