The Enhancement Of Osteogenic And Antibacterial Efficacies Of Orthopaedic Indwelling Materials With Novel Nano-vanadium Dioxide Films

ObjectiveVanadium is a trace element in the human body,and vanadium compounds have a promising future in biological and medical applications due to their various biological activities and low toxicity.Herein,we evaluated the biocompatibility,osteogenic effect and antibacterial effect of nano vanadium dioxide films.MethodsA novel pure vanadium dioxide?VO₂?nanofilm was deposited on a substrate of biomedical titanium by magnetron sputtering.In in vitro experiments,the biocompatibility of nano VO₂ films was evaluated using rBMSCs?rat bone marrow mesenchymal stem cells?by several methods?evaluating cytotoxicity by the live/dead cell viability assay,cell proliferation and viability by the CCK-8 assay,cell adhesion and spreading by phalloidin and DAPI staining and cell morphology by SEM?;the osteogenic effect of the samples was examined by a series of assays?including ALP activity visualization by ALP staining and quantification using an ALP assay kit,ECM visualization and quantification by alizarin red staining and osteogenic activity quantification by qRT-PCR?,and we utilized oxidation-sensitive fluorescence probe DCFH-DA to evaluate if VO₂ nanofilms were able to ameliorate the high ROS?reactive oxygen species?level of rBMSCs and subsequently promote osteogenesis;the antibacterial effect of the samples was evaluated against MRSA?methicillin-resistant Staphylococcus aureus?by multiple methods?including quantitative antibacterial effect evaluation by SPM,qualitative anti-biofilm effect evaluation by LIVE/DEAD BacLight staining and qualitative anti-adhesive bacterial ability evaluation by SEM?.As for in vivo researches,an SD?Sprague Dawley?rat implant-related osteomyelitis model was used to examine the antibacterial effect of the VO2 nanofilms by X-ray,Micro-CT analysis,SPM and histology.ResultsThe antibacterial effect of nano VO2 flims were validated systematically by in vitro and in vivo assays.The biocompatibility and osteogenic effect of the samples were illustrated by a series of methods.In addition,we validated that one possible mechanism of the osteogenic effect of VO₂ involved the amelioration of high ROS levels and the attenuation of the oxidative stress inside the rBMSCs caused by foreign body response upon the implantation of indwelling materials.ConclusionsThe present work confirmed the simultaneous osteogenic and antibacterial effects of nano VO₂ films,and the excellent effects may originate from its differential regulation of ROS levels in rBMSCs and bacteria according to the results of our present and previous studies.This study is the first to report the simultaneous effects of VO₂ on bactericidal and osteogenic activities through its differential modification of ROS activity in eukaryotic?rBMSCs?and prokaryotic?MRSA?cells.The findings in this work may yield a deeper understanding of the biological activities of vanadium compounds while also paving the way for the further investigation and application of VO₂ in biological and medical materials.