The Research Of A Short-term Absorbable Bone Wound Hemostatic Nano-BG/CS/CMC Composite Materials

As a classic hemostasis material of bone defects, bone wax has been used for more than a century. Due to bone wax’s immediacy and effectiveness of hemostasis, ease of use, low cost, it is still being widely used in different surgeries. But in fact, surgeons minimize the amount of bone wax used interoperatively for the increasing number of negative reports about it[18,19]. Numerous complications have been attributed to bone wax because it is an nondegradable material, and, hence, remains indefinitely at the site of application. Thus, alternative topical hemostatic agents with good histocompatibility, osteoconduction, suitable degradation rate and porosity has been researched[1].Chitosan (CS) is a linear polysaccharide derived from partial deacetylation of chitin. It is accepted as an similar substitute material for bone defects because of high biocompatibility, osteoconductivity, antimicrobial, suitable biodegradability and adsorption properties[2]. These properties make it well suited for wound closure and healing in various animal models as well as hemostasis in vitro. The hemostasis principle of bone wax is just physical plugging. Platelet adhesion and activation are also crucial events, to promote thrombus formation that prevents further bleeding. These events have been analysed in vitro and the ability of chitosan to promote erythrocyte aggregation had been reported[3].The use of bioactive glass may be a strategy to provide osteoconductive properties to the composite. For example, bioglass (BG) is a bioactive material in the Na2O/CaO/SiO2/P2O5system, which was found to spontaneously bond to living bone without forming a fibrous tissue at the interface. BG on the apatite layer exhibits a very distinct viscoelastic and mechanical characteristics from polymeric matrices. Composite scaffolds with high porosity demonstrated that the composite scaffolds showed better biocompatibility than chitosan scaffolds[4].The water-soluble negatively charged polyelectrolyte carboxymethyl cellulose(CMC)(C6H7O2(OH)2CH2COONa) is an important cellulose derivatives through chemical modified from natural cellulose. Due to the unique characters of CMC such as adhesiveness, thickening, the film forming ability, suspension property and water stability, it is widely used in industry as a thickener, as an additive in washing powders, for paper making, or as a flotation agent. However, there is few reports about using CMC in the field of bone regeneration. Kim[5] examined the possibility of creating in situ-forming gels from sodium carboxymethylcellulose (CMC) as an in vivo carrier of demineralized bone matrix (DBM), and the conclusion is encouraging. Because of the same structure and opposite charges, when CMC mixed with CS in the solution, strong ionic crosslinking will lead to the formation of a stable polyelectrolyte network structure.To our knowledge, there is a dearth of research using bioactive glass/chitosan/carboxymethyl cellulose (nBG/CS/CMC) composite scaffold for bone defect. Our purpose, therefore, was to design a composite scaffold with the three materials, and test it in vitro and in vivo. We hypothesized that nBG/CS/CMC scaffolds can serve as a potential material for bone repairing and hemostasis in critical sized bone defects. Part oneComposite preparation, characterization and in vitro cell experimentPurpose:Research the feasibility of nBG/CS/CMC compounds as a kind of bone repair material in the non-bearing parts.Methods:Determine the proportion of components through testing different mass ratio of nBG/CS/CMC composites. The microstructures of the three-dimensional (3-D) porous scaffolds of nBG/CS/CMC with lyophilization method were analyzed with SEM. Based on the quantitative analysisof at least40micrographs, both the material pore diameters and porosity were calculated by ImageJ software. Cell viability was determined using a WST-1Assay Kit with rabbit Synovium-derived mesenchymal cells (SMSCs).Results:Mass ratio of nBG/CS/CMC component is1:1:3.75. The Scanning Electron Microscope micrograph demonstrated the open and interconnected porous structure, the porosity is greater than80%, the average pore diameter is78.3+28.1um. The WST-1Assay indicated the nBG/CS/CMC composite scaffold have excellent biocompatibility and no cytotoxicity.Conclusion:The microstructure of nBG/CS/CMC composite was similar with natural bone framework and the material has good biocompatibility. Part TwoUsing composite for bone surface hemostasis and bone repairPurpose:Study the in vivo degradation, bone surface hemostasis and bone repair of nBG/CS/CMC composite.Methods:27rabbits were used in the in vivo test. In3,6,9weeks,3rabbits in each group were executed respectively. X-ray, H&E and Masson’s staining were analyzed for the evaluation of bone in-growth and bone quality. The degradation of the implant composite was calculated by ImageJ software.Results:Though nBG/CS/CMC composite have the same hemostasis effect with bone wax, its appropriate biodegradation rate and satisfying osteoconductive ability may be beneficial for bone repairing.Conclusion:Our findings suggest that nBG/CS/CMC scaffolds can serve as a potential material for bone repairing and hemostasis in critical sized bone defects.