Research On Design Of Biomimetic Gradient Biodegradable Bone Tissue Engineering Materials

Repairment of bone defect is one of difficulties in clinic. Many researchers havetried to solve the problem by fabricating more kinds of biomimetic materials. But theyare only devoted to researching on cartilage tissue, and few researches on hard tissuecan be found. Therefore, the this project is to study a biomimetic bone materials withgradient structure and biodegradability, the purpose is to prepare a bone repairmaterial with the structure and mechanical properties as autogenous bone.This paper was mainly done two aspect works as follows:(1) Hydroxyapatite(HA) was selected as raw materials of biomimetic cancellous bone. Microwavesintering was used to prepare biomimetic cancellous bone which had the similarcomposition and structure to the autologous bone, and its biological activity wastested.(2) Pure magnesium (Mg) was selected as raw materials of biomimetic corticalbone. Firstly, both of biodegradability and bio-osteoinductivity of pure magnesiumwere tested in vitro and in vivo. Secondly, laser surface-patterned was used toenhance osteoinductive of surface of simple. Finally, mechanical properties of porousMg plate were simulated by ANSYS software.The results can be listed as follows:(1) When sintering power and sintering timeof microwave sintering are600W and15min, the sample was composed of β-TCPand HA.(2) After static immersing in simulated body fluid (SBF) for18d, bone-likeapatite was formed on the surface and section of sample after sintering. So the samplehas good bio-osteoinductivity and three-dimensional through-hole structure.(3) Invitro, after immersing in SBF, the degradable rate of pure Mg gradually slow down,and eventually reach to a balance value. After immersing for20h, corrosion productslike apatite were formed on the surface.(4) In vivo, the result shown that pure Mg hasa good biodegradability. However, the animals have discomfort phenomenon becauseof the excessive amount of hydrogen generating and poor osteoinductivity.(5) Aperiodic V-shaped groove structure was produced on the surface of pure Mg by lasersurface-patterned. This structure is conducive to the deposition of calcium andphosphorus ions, and it played a role in improving the surface bioactivity.(6) Theresult of tensile test proved the reliability of simulation of the mechanical propertiesof pure magnesium by ANSYS software. Through simulate the mechanical properties of the porous plate, it meet the need of mechanical properties of human bone when thenumber of holes is60, and the porosity is15.072%.