3D-printed scaffolds repair infected bone defects / 中国组织工程研究

ABSTRACT

BACKGROUND:At present,the treatment of infected bone defects has the problems of long course of disease,poor treatment effect and high cost.The osteogenic effect of personalized bone replacement materials in clinical treatment is limited.Therefore,a 3D-printed bone graft material with both good osteogenic effect and antibacterial effect is urgently needed for clinical treatment. OBJECTIVE:To summarize the research status of 3D-printed scaffolds loaded with antimicrobial agents for the treatment of infected bone defects. METHODS:PubMed,Web of Science,Elsevier,and CNKI databases from January 2010 to June 2022 were searched for related articles.The Chinese search terms were"bone defect,3D printing,scaffold material,antibacterial,animal experiments,in vitro experiments".English search terms were"bone defect,3D printing,scaffold,antibiosis,animal experiment,in vitro".Finally,60 articles were included for review and analysis. RESULTS AND CONCLUSION:The 3D scaffolds made of titanium,magnesium,tantalum and other metals and their alloys have certain osteogenic properties,but do not have antibacterial function.Hydroxyapatite and other bioceramic materials have good biocompatibility and are prone to be degraded,whereas due to the lack of strength,they are usually combined with artificial polymer materials to form composite materials,which respectively mimic the inorganic and organic components in natural bone,and play their respective excellent functions.Antibiotics,silver/copper nanoparticles,antimicrobial peptides,gallium and other antibacterial agents play an antibacterial role by destroying bacterial cell membrane,producing reactive oxygen species to interfere with bacterial DNA replication,inhibiting iron absorption and other mechanisms.As a result,the 3D-printed scaffold has both antibacterial and osteogenic effects.However,there are still some problems such as drug resistance and difficult to control effective concentrations.3D-printed scaffolds are often loaded with antibacterial agents by loading drug-loaded microspheres on scaffolds,preparing antibacterial coating on the scaffold surface,and participating in joint 3D printing with drugs.The loading mode of antibacterial coating prepared on the scaffold surface is the most widely used,and its antibacterial effect is more stable.Nonetheless,the selection of the most suitable loading mode for antibacterial agents needs to be further discussed and summarized.It is a future research prospect to optimize the mechanical properties of composite scaffolds and prepare biomimetic bone scaffolds so that the degradation rate is consistent with the bone reconstruction rate in infected bone defects.The ideal antibacterial agents may play a role through a variety of antibacterial mechanisms,thus being expected to play a good antibacterial effect through low antibacterial concentration,which should be a hot spot of anti-bone infection research.After loading antibacterial agents on the surface of the scaffold,antibacterial agents can"intelligently"react to the local microenvironment,achieving controlled release,and regulating the osteogenesis,vascularization and immune response of the microenvironment,which is the focus of current research.