Preparation And Characterization Of Antibacterial/Antiinflammatory Tissue Repair Scaffolds

Proper repair for tissue defect caused by trauma,disease and other factors has become an important issue in clinic.Tissue engineering technology provides a good solution for the repair of clinical tissue defects,but the infectious wounds and aseptic inflammation greatly limited this repair effectiveness.Therefore,it is important to reduce the threat of infectious inflammation/ aseptic inflammation during the process of tissue repair.In this study,Berberine-Oleanolic acid,a new functional Chinese medicine compound,was used as a bioactive factor to develop the functional tissue engineering scaffold,which may provide a new strategy for the repair of tissue defects under pathological inflammation or bacterial infection.The specific research contents of this paper are as follows:(1)For bacterial infectious inflammatory wounds,in this study,a scaffold with antimicrobial effect was prepared by compounding the Berberine-Oleanolic acid with collagen materials,which provides a new treatment scheme for tissue repair and reconstruction.Firstly,the bacteriostatic properties and biocompatibility of Berberine-Oleanolic acid,Berberine hydrochloride and Berberine sulfate were investigated,the experimental results showed that Berberine-Oleanolic acid exhibited more excellent bacteriostatic efficacy and biocompatibilit y than Berberine hydrochloride and Berberine sulfate.Then,Berberine-Oleanolic acid/collagen porous scaffolds were prepared by physical blending combined with the freeze-drying method,the results showed that the prepared drug-loaded collagen scaffolds had a uniform porous threedimensional structure,the pore size was about 125 μm,the porosity was more than85%,and the water absorption was up to 2500%,which was suitable for tissue engineering.Drug release data showed that the drug-loaded scaffolds released 85% of the antimicrobial drugs within 1 day and could maintain a continuous and stable release for 15 days.Drug-loaded collagen scaffolds showed a slow and uniform degradation trend within 2 months.The bacteriostatic results showed that the collagen scaffolds with 3%,4% and 5% drug loading had strong inhibitory ability against Staphylococcus aureus and Escherichia coli,especially with higher sensitivity to Staphylococcus aureus.Cell proliferation data and FDA staining results showed that there was no significant difference in the proliferation rate of MG-63 cells on collagen scaffolds with drug loading of 1%,2% and 3%,compared with pure collagen scaffolds,and MG-63 cells adhered well and proliferated normally after implantation on the scaffolds.In conclusion,the collagen scaffold with 3% drug loading has good biocompatibility and excellent antimicrobial activity,which is expected to be widely used and developed in tissue engineering and wound repair.(2)For the aseptic inflammation environment,Berberine-Oleanolic acid loaded silk fibroin fibrous scaffolds were prepared by electrospinning combined with physical blending method.Silk fibrous scaffolds with suitable fiber structure were prepared by optimizing the spinning parameters.Then silk fibroin scaffolds with different drug loadings were prepared,the fiber surface was smooth,without particle aggregation and beading,and the fiber diameter distribution was uniform.Drug release curves showed that drug-loaded scaffolds could release drug stably for 14 days,showed a trend of long-term release.The mass loss was uniform during degradation and the p H value of the scaffolds changed slightly during degradation process,which was suitable for the growth of new tissues.Cytological experiments showed that rabbit articular chondrocytes could adhere and proliferate on drug-loaded silk fibrous scaffolds with normal cell morphology,indicated that the scaffolds had good biocompatibility.The in vitro inflammation model was induced by IL-1β,the results showed that the morphology of chondrocytes on drug-loaded fibers under inflammation enviroments was more similar to that of chondrocytes on pure silk scaffolds under normal environment,indicating that Berberine-Oleanolic acid could effectively resist the stimulation of inflammatory factors,protected the activity of chondrocytes and inhibited the dedifferentiation process of chondrocytes.In summary,based on the bacterial infectious inflammation and as eptic inflammation environment during tissue reconstruction,the functional scaffolds combined with the advantages of active ingredients of traditional Chinese medicine were prepared in this study,it may laid a basic foundation for solving the inflammation and infection problems in tissue repair process,and also broadens the application of functional tissue engineering scaffolds in tissue repair and reconstruction.