Preparation And Research Of Composite Nanofiber Scaffold Based On Polycaprolactone

At present,bone tissue engineering is still an ideal way to treat bone injuries,and the construction of bone tissue scaffolds is the core of it and has been extensively studied.However,it is difficult for a single bone tissue scaffold material to meet its complex requirements as an implant at the same time.Polycaprolactone(PCL)has become a widely used tissue engineering scaffold material due to its good biocompatibility and biodegradability.Among them,PCL nanofiber scaffolds prepared by electrospinning technology are also attracting attention,but they also exist some shortcomings,such as insufficient mechanical properties,insufficient biological functions,etc.As bone tissue implant materials,they should also have certain osteoinductive function,anti-inflammatory and anti-oxidative stress ability.In order to solve the above problems,this paper adopts electrospinning technology,using polycaprolactone as the base material to do surface mixing and modification to prepare a composite nanofiber scaffold based on polycaprolactone,the structural characterization and biological properties were studied to explore its possibility as a bone scaffold material.The main research contents are as follows:(1)Blending lignin(LIG)into polycaprolactone(PCL),preparing PCL/LIG composite fiber scaffold material through electrospinning technology,and then attaching ZIF-8 metal organic framework through surface modification.A coating is formed on the fiber scaffold material to prepare a PC L/LIG/ZIF-8 composite fiber scaffold.It was characterized by the successful hybrid modification of lignin and ZIF-8 coating,and the hydrophilicity a nd mechanical properties of the modified composite fiber were greatly improved.Among them,the contact angle of the PCL/LIG/ZIF-8 composite fiber is 24.2°,and the tensile strength reaches 3.37 MPa,both showing better performance.In addition,due to the mixing of lignin to fibers,the composite fiber scaffold exhibits good oxidation resistance and degradation rate.The ZIF-8 metal organic frame coating gives the composite fiber stent antibacterial property,and its antibacterial rate is close to 100%.In the osteogenic activity experiment,the PCL/LIG/ZIF-8 composite fiber scaffold showed the best osteogenic differentiation induction performance,and obvious mineralization can be seen and related osteogenic genes have also been expressed.The above results indicate the successful preparation of the PCL/LIG/ZIF-8 composite fiber scaffold,which is a composite scaffold material with good surface properties and biological versatility.(2)Use dopamine modification technology to load a layer of polydopamine(PDA)on the polycaprolactone electrospun fiber as an intermediate layer,and modify different concentrations of copper ions(0.02,0.1,0.5 mol/L)into the polycaprolactone The surface of the ester/dopamine forms a PCL-PDA-Cu composite fiber scaffold.Through the characterization,the successful loading of PDA and C u²⁺can be obtained.Through the water contact angle and mechanical property test,it is found that the addition of PDA coating will significantly improve the hydrophilicity of the fiber scaffold.Amo ng them,the hydrophilicity of PC L-PDA fiber is the best.The angle is 24.5°.With the addition of copper ions,the hydrophilicity of the fiber scaffold will decrease.PC L-PDA-Cu0.5 composite fiber shows the best mechanical properties.The study of antibacterial performance shows that with the increase of C u ion concentration,the antibacterial properties of the fiber gradually increase,and the antibacterial rate of the PCL-PDA-Cu0.5 composite fiber to the two kinds of bacteria is above 95%.Using r BMSCs c ells to evaluate the biocompatibility of composite fiber scaffolds,compared with pure PCL fibers,other fiber scaffolds show better cell proliferation ability,and the cell morphology is also normal multilateral stretched growth.Compared with the PCL-PDA composite fiber scaffold,the PCL-PDA-Cu composite fiber scaffold with different concentrations of copper ions did not show much different cell proliferation ability,but all showed good biocompatibility.