In Situ Bioinspired Preparation And Biological Study Of Facilitated Endogenous Bone And Osteochondral Repairing Materials

Bone-based tissue injury,such as common hard tissue and osteoarthritis,caused by trauma,disease,accident and aging,is a difficult problem in clinical treatment.In view of this,the treatments of common hard bone tissue injury and osteochondral injury caused by human osteoarthritis were investigated in the study,respectively.The main contents and results of the study are as follows.1.Biomimetic construction and characterization of GO/CS/n HAP composite in situ inducing osteogenesis.Refer to the idea of bionics,the study utilized in situ biomimetic synthesis method and freeze drying technology to keep soluble calcium salt and phosphate uniformly depositing on chitosan(CS)and graphene oxide(GO)complex template with covalent binding,which effectively regulated the nucleation and growth of nano hydroxyapatite(n HAP)on organic template.Thus,the GO/CS/n HAP bioactive composite scaffolds with multiple pore structures and specific morphologies were prepared by one step process.In the study,four kinds of GO/CS/n HAP scaffolds were prepared with different contents of GO(i.e.0,0.02%,0.09% and 0.13%).The study showed that the composite materials had multiple bone-like micro-nano pore structure,and n HAP were uniformly distributed on the surface of the scaffold.With the addition of GO,thermal stability,water absorption/retention and degradation rate of scaffolds were improved.And scaffold with 0.09% GO could rapidly induce the in situ nucleation and growth of n HAP when it immerged in the simulated body fluid(SBF).It showed 50% recoverable deformation.Meanwhile,lower hemolysis rate and high protein adsorption performance also showed great biocompatibility of scaffold.2.Construction and characterization of integrated osteochondral repair scaffolds with biomimetic gradient structure.Through coprecipitation and freeze drying process,biomimetic rebuilding of human articular osteochondral tissue in structure,composition and function was achieved.Cartilage layer of osteochondral scaffolds were prepared with sodium hyaluronate(SH)and CS,and subchondral bone layer were with GO,CS and n HAP.Four types of scaffolds were prepared by adjusting SH content(i.e.S-0,S-1,S-2 and S-3).Series of characterization results showed that the prepared scaffolds had the upper and lower two-phase structure as well as the integrated continuous interface between cartilage and subchondral bone layer.In addition,SEM-mapping indicated that n HAP on scaffold showed a biomimetic gradient distribution from the cartilage layer to the subchondral bone layer.Moreover,the scaffolds shows a interpenetrating multistage hole structure.With the addition of SH,the scaffold showed good water absorption/retention,stable swelling rate,appropriate degradation rate and good biomineralization ability.Finally,the two-phase structure of the optimal component scaffold(S-2)was also characterized and found that the pore size and porosity gradually decrease from cartilage to subchondral bone layer,whereas mechanical properties showed an increasing trend.Through further in vivo and vitro biological studies,it was found that 3D scaffold materials of the two systems could not only enhance the attachment and proliferation of osteoblasts and bone marrow mesenchymal stem cells,but also promote the expression of related genes and proteins of osteogenesis and cartilage.Thus,they can effectively induce the growth and healing of hard bone and articular osteochondral defects.Therefore,it is hopeful to realize its potential application value in the field of hard bone tissue injury repair and osteoarthritis treatment.