Preparation And Properties Of Collagen Ultra-thin Film Bio-bone Scaffold

Bone defects are a huge challenge in the field of plastic surgery reconstruction.The most common treatment method for bone defects in the clinic is bone transplantation.Bone graft is mainly divided into autogenous bone transplantation and allogeneic bone transplantation.However,autologous bone transplantation often fails to meet the demand for large clinical due to shortcomings such sa limited supply,easy infection and new trauma.The structure of biological bone in the allogeneic bone is similar to that of human cancellous bone.It has the advantages of natural mesh pore system,good biocompatibility and conductive bone formation,which meets the physiological requirements of bone repair.It can be used as a scaffold for bone tissue engineering.However,after deproteinization of biological bone,there are defects such as poor mechanical properties,insufficient biocompatibility and weakened osteogenic activity,which limits its clinical application.Therefore,modifying the surface of the biological bone scaffold to improve the osteogenicity of the biological bone is of great significance in the clinical application of bone graft materials.At present,collagen is widely used as a biomaterial for tissue-engineered bone,and it has low immunogenicity,good biodegradability and biocompatibility.Poly-L-Lysine has an electrostatic adsorption function,and it is often used as an adhesion factor.In this study,PLL cross-linked collagen is used to construct a collagen nano-thin film,and the surface of the biological bone scaffold is modified to improve the bone regeneration of the biological bone scaffold in the repair of bone defects.Objective:A collagen ultra-thin film is prepared so as to evenly coat the surface of the biological bone scaffold,thereby constructing a micro-environment that conforms to adherence,growth,differentiation and functional expression of transplanted cells.At the same time,the physicochemical properties of the collagen ultra-thin film bio-bone scaffold were detected,and the adhesion,proliferation,and distribution of BMSCs in the composite scaffold were observed.A preliminary study on the osteogenesis ability of collagen ultra-thin film biological bone,which will provide a theoretical basis for the clinical application of collagen ultra-thin film biological bone.Methods:(1)Collagen ultra-thin film biological bone scaffold is prepared by solution deposition freeze-drying method;(2)Observation and detection of the physical and chemical properties of collagen ultra-thin membrane bio-bone scaffold materials.Such as morphological appearance,porosity,mechanical properties,X-ray diffraction,and energy spectrum analysis;(3)The BMSCs of SD rats were co-cultured with collagen ultra-thin membrane biological bone scaffold.And scanning electron microscopy(SEM)was used to observe the adhesion,proliferation and distribution of BMSCs on the surface of collagen ultra-thin bio-scaffolds.Results:(1)The antigen component in biological bone was successfully removed by chemical method.And the biological bone scaffold with three-dimensional porous network structure was obtained.Its main inorganic phase is hydroxyapatite[Ca10(PO4)6(OH)2];(2)After the bio-bone scaffold is modified by PLL-coated collagen ultra-thin film.A uniform ultra-thin substance is formed on the surface of its micropores;(3)Compared with the bio-bone scaffold without any treatment,the mechanical strength of the collagen ultra-thin film bio-bone scaffold material has been reduced.But its percentage of calcium and phosphorus elements has increased;(4)Scanning electron microscopy found that the number of cell proliferation on the surface of the collagen ultra-thin biological bone scaffold is the largest,and the cells are in good condition and malleable.Conclusion:The PLL cross-linking method is used to make the collagen form a super-thin film structure to uniformly cover the surface of the biological bone scaffold material,and the original characteristics of the collagen are not changed.Compared with pure bio-bone and collagen/bio-bone scaffold materials,collagen ultra-thin bio-bone is more conducive to the adhesion,proliferation and growth of BMSCs,has better cell compatibility and promoting osteogenesis,and is expected to become an efficient tissue-engineered bone repair materials.