Antibacterial 3D Printed Silver Nanoparticles/Poly Lactic-Co-Glycolic Acid(PLGA) Scaffolds For Bone Tissue Engineering

ObjectiveThe repair of bone defects presents a significant challenge in clinical practice,and the repair of infectious bone defects is another major problem facing humanity.To address this issue,traditional antibiotic-laden scaffolds have been used for antibacterial purposes.However,the emergence of antibiotic-resistant bacteria in recent years has posed new challenges.This study introduces the use of silver nanoparticle(AgNPs)as an antibacterial material,as no evidence of nanosilver resistance exists.AgNPs was blended with polylactic acid-ethylene glycol(PLGA),a biocompatible and biodegradable material,to create a bone tissue engineering scaffold that possesses both antibacterial properties and promotes bone repair.MethodsIn this study,the preparation of AgNPs/PLGA antibacterial scaffolds was completed using direct ink write(DIW)3D printing technology.Three bone scaffolds were prepared with three different mass ratios,namely wt 3%,wt 1%,and wt 0.1%,corresponding to3 AgNPs/PLGA,1AgNPs/PLGA,and 0.1AgNPs/PLGA,respectively.A control group of pure PLGA scaffolds was also set up.Scanning electron microscopy(SEM)was used to observe the microstructure and surface morphology of the scaffolds,and a tensile machine was used to measure the mechanical properties of the scaffolds,calculating the Young’s modulus of AgNPs/PLGA scaffolds to evaluate their mechanical performance.Inductively coupled plasma atomic emission spectroscopy(ICP)was used to measure the silver ion concentration in the solution that had been soaked in the scaffold,to evaluate whether the scaffold silver ions were continuously released.The biocompatibility of the scaffold was assessed by CCK-8 assay,live/dead staining assay and biomineralisation assay.The antibacterial properties of AgNPs/PLGA scaffold were tested with Staphylococcus aureus and Escherichia coli.ResultsThe Energy Dispersive Spectroscopy(EDS)analysis confirmed the presence of silver nanoclusters in the AgNPs/PLGA scaffolds,and both SEM and EDS showed that AgNPs were uniformly distributed inside the scaffold without aggregation.Observed under SEM,the surface of the AgNPs/PLGA scaffold was uniform with a porous structure and interconnected pores.The tensile test results showed that the Young’s modulus of PLGA was 1.96±0.03 GPa.For the AgNPs/PLGA scaffold,the Young’s modulus gradually increased with the increase of AgNPs concentration,respectively 2.28±0.04 GPa,2.44±0.08 GPa,and 2.46±0.08 GPa.The release curve of silver ions confirmed the fast initial release and sustained release of AgNPs/PLGA.All scaffolds with silver nanoclusters showed anti-bacterial activity.Cytotoxicity experiments have demonstrated that AgNPs/PLGA scaffold is non-cytotoxic and favours cell proliferation.The results of biomineralisation experiments show that hydroxyapatite can be generated on the scaffold.ConclusionThe research demonstrates that AgNPs/PLGA scaffolds produced via DIW printing have excellent biomechanical performance due to the enhanced rigidity provided by the addition of AgNPs.This implies that the scaffold has the capability to remain in place within the body and provide mechanical support for bone tissue growth when applied,making it suitable for use in bone tissue engineering.Additionally,the scaffold has an optimal pore size for bone tissue cell infiltration,adhesion,and growth,and promotes blood vessel growth,which provides essential nutrition for bone tissue growth.The scaffold’s antibacterial properties have been confirmed through tests with Staphylococcus aureus and Escherichia coli,showing that it can effectively inhibit their growth,making it an ideal choice as an antibacterial scaffold.Mixing AgNPs and PLGA results in even distribution of AgNPs within PLGA.The release rate of silver ions from the scaffold was tested using inductively coupled plasma and by observing color changes after soaking in simulated body fluid.The results showed that the scaffold can continuously release silver ions,ensuring its long-term antibacterial effectiveness.In vitro cell experiments showed no toxicity,which provides a foundation for its potential use in the human body.The ability of hydroxyapatite to form on the scaffold,as evidenced by mineralisation experiments,indicates good biocompatibility of the scaffold.Overall,the results suggest that the AgNPs/PLGA scaffold produced by DIW 3D printing technology holds significant potential for use in bone tissue engineering.It offers not only the ability to prevent bone tissue infections but also promotes bone tissue repair,providing a feasible plan for treating infected bone defects,and has the potential to become a new treatment method in future developments.