Preparation And Properties Of Three-dimensional Network Structured MBGs Nanotubular Scaffolds Templated By Bacterial Cellulose

Bone defects have a significant effect on the structure and function of body.The small defects could be reconstructed spontaneously,while it could not be achieved for large bone defects.Therefore,it is imperative to implant biomaterials to repair damaged tissue.Currently,the autologous bone grafting,alloplastic implants and artificial bone grafts are the main methods to deal with bone defects in clinical treatment.To our best knowledge,autogenous bone graft is considered to be the most effective methods due to its high therapeutic efficiency.However,problems of reoperation,limited tissue availability and infection hamper its clinical application to some extent.Allograft is another effective method,but problems coupled with its application are disease transmission,immunoreactions and high cost.Hence,preparing an ideal bone tissue engineering scaffold with highly biomimetic ECM,excellent biocompatibility and superior bone regeneration capacity is a hot topic in bone tissue engineering.Furthermore,scaffold materials not only need excellent physicochemical properties and osteoconductivity,but also need to effectively combine with growth factors or drugs for promoting bone defect repair.Additionally,infection often occurs in wound during bone repair,therefore it is of crucial significance to develop multifunctional bone tissue engineering scaffolds with antibacterial properties.Interestingly,previous reports have revealed that Cu ion has antibacterial capacity.Hence,it is expected that incorporation of Cu into mesoporous bioactive glass can not only up-regulate their osteogenic potential,but also endow mesoporous bioactive glass with additional antibacterial property.In this investigation,a novel type of mesoporous bioactive glass scaffold applied to drug controlled system was fabricated using sol-gel procedure in combination with nonionic block copolymer EO₂₀PO₇₀EO₂₀(P123,M_w=5800)and bacterial cellulose as structure-directing agent,and then evaluated the morphology,structure,in vitro bioactivity,capacity of drug loading and releasing kinetics as well as biocompatibility.The main contributions of the investigation were summarized as follows:the result of N₂ adsorption-desorption depicted that the mesoporous bioactive glass nanotube scaffold possessed high specific surface area.With the increasing of P123 contents,the specific surface area of mesoporous bioactive glass nanotube scaffold was up-regulated.Besides,the effect of Cu contents on the textural features of mesoporous bioactive glass nanofiber scaffold was also investigated.According the results of N₂adsorption-desorption,it could be found that the specific surface area of the mesoporous bioactive glass nanofiber scaffold decreased after incorporating parts of Cu.Furthermore,the results of in vitro bioactivity certified that mesoporous bioactive glass nanotube scaffold possessed excellent apatite-forming ability.However,the incorporation of Cu into the mesoporous bioactive glass nanofiber scaffold slowed the conversion of the scaffold to hydroxyapatite,but the effect was not significant.According to the result of drug loading,it could be concluded that the drug loading amount of mesoporous bioactive glass nanotube scaffold improved with the increase of simvastatin and rh BMP-2 concentrations.The release kinetics certified that the release amount was associated with the loading concentration of simvastatin and rh BMP-2,it observed that the mesoporous bioactive glass nanotube scaffold could be achieved the sustainable release of simvastatin and rh BMP-2,respectively.The biocompatibility test revealed that the loading of simvastatin and rh BMP-2 enhanced the proliferation and differentiation of h BMSCs as compared to bare mesoporous bioactive glass nanotube scaffold.According to the results of anti-bacterial analysis,it was observed that the Cu-doped mesoporous bioactive glass nanofiber scaffolds could retard bacterial viability when compared to pure mesoporous bioactive glass nanofiber scaffold throughout the experiment period,confirming that incorporation of Cu ion into the scaffold endowed them antibacterial property.Moreover,it was found that the antibacterial activity was significantly depended on the Cu content in the scaffold and species of implanted bacteria.Mesoporous bioactive glass nanofiber scaffold containing larger amount of Cu displayed more antibacterial activity.Furthermore,the Cu-doped mesoporous bioactive glass nanofiber scaffold was found to be more bacterial virulence against gram-negative E.coil versus gram-positive S.aureus bacteria.