Preparation And Performance Study Of Layer-by-layer Assembled Woven Bone Scaffold

With the study of artificial bone scaffolds,some biophysical factors have been found to affect cell behavior.Bioelectrical signals are important factors in maintaining cell function and affecting cell behavior.Conductive polymers(CPs)can promote cell activity and enhance signal transduction between cells,which has attracted attention in tissue regeneration.How to apply CPs to scaffolds and combine them well with cells has become a research focus.In this study,layer-by-layer assembly strategy was used to grow different coatings on Polyvinyl alcohol/Polylactic acid(PVA/PLA)braids to prepare a braided bone scaffold with electrochemical activity,biological activity,and biocompatibility.The main research contents are as follows:Firstly,the PVA/PLA braids were immersed in dopamine solution to deposit polydopamine(PDA)coating.After soaking for 4 h,the fiber surface was uniformly wrapped by PDA,and the electrochemical deposition of scaffolds treated with 4h PDA could better induce the formation of hydroxyapatite(HA)coating on scaffolds.Spherical HA was induced on the surface of scaffold by immersion in simulated body fluid(SBF).Compared with pure PVA/PLA banding,the cell activity of scaffolds increased by 41.6 %.Then,to increase the electrochemical activity of the scaffold,conductive polymer polypyrrole(PPy)was introduced to form conductive coating in situ on the scaffold.When the pyrrole concentration is 0.5 M,a dense conductive film is formed on the fiber with low resistance and electrochemical impedance.After immersion in PDA for 4 h,HA coating was electrodeposited to explore the best deposition current density.The results showed that the electrochemical properties of the prepared composite coating scaffolds were stable,and the cell activity of the scaffolds was increased by 188 %.Finally,by changing the direct deposition method of PDA on PPy scaffolds,pyrrole and dopamine with different concentration ratios were polymerized on PPy scaffolds by spraying method,and the influence of different concentration ratios on the performance of scaffolds was explored.Compared with PDA/PPy scaffolds,scaffolds with different concentrations of pyrrole and dopamine ratios showed higher electrical conductivity.The CV curve of HA/PPy@PDA scaffold remained stable by cyclic voltammetry.The ability of scaffolds to induce HA formation in SBF was used to evaluate the in vitro mineralization ability of scaffolds.Compared with scaffolds without HA coating,HA/PPy@PDA scaffolds induced more HA formation and had stronger bone mineralization ability.MTT experiment showed that the cell activity of the composite coating scaffolds was increased to 240.9 %,which could promote cell proliferation and growth.This study provides a research idea for the structural design of layer-by-layer assembled braided bone scaffolds and extends the application of textile structures in bone tissue engineering.