Regulation Of V₄C₃ MXene Antioxidant And Pro-oxidation Activities For Biological Application

The ultra-thin lamellar structure of two-dimensional MXene materials has the advantages of large specific surface area,high conductivity and abundant catalytic active sites.At the same time,abundant valence state composition and surface adjustable functional groups provide more possibilities for biomedical applications.However,its irreversible and uncontrollable structural oxidation process in aqueous solution is considered to be one of the main factors limiting its application.At present,some researchers have preliminatively explored the autoxidation process of two-dimensional MXene materials and tried to slow down its oxidation rate through different methods.However,few studies have been proposed on the fine regulation of the oxidation process of two-dimensional MXene materials and the related biophysical effects.In this paper,two-dimensional V₄C₃MXene was used as a model to regulate its surface valence state composition by reasonable temperature control oxidation means,and a variety of characterization analysis techniques were used comprehensively to explore the transformation of its broad-spectrum antioxidant and pro-oxidation activities during the oxidation process,revealing the biophysical effect transformation mechanism mediated by MXene valence engineering.It has been applied in disease treatment and biomolecular detection to provide a new idea for the design of anti-oxidation and pro-oxidation materials.The main research content of this paper is as follows:（1）V₄C₃nanosheets（NSs）with broad-spectrum antioxidant activity in the treatment of pulmonary fibrosis.In this study,we designed and synthesized a novel V₄C₃nanosheet antioxidant,and characterized its microscopic morphology,electronic structure and valence state composition by SEM,TEM,XPS and ESR.The scavenging ability of reactive oxygen and nitrogen radicals was systematically evaluated by UV-Vis and ESR.The results show that weak autooxidation can adjust the valence composition of V₄C₃nanosheets and significantly improve the broad-spectrum oxidation resistance.Valence engineering triggers a variety of antioxidant mechanisms,such as electron transfer,H atom transfer and enzyme-like catalysis,so that V₄C₃NSs has a broad spectrum,efficient and durable antioxidant capacity.With superior antioxidant properties and high biocompatibility,V₄C₃NSs significantly prevents myofibroblast proliferation and extracellular matrix abnormalities,thereby alleviating the progression of bleomycin-induced pulmonary fibrosis in animal models by clearing ROS,anti-inflammation,and rebuilding antioxidant defenses.This study not only provides important strategies for the design of antioxidant nanomaterials,but also provides a nano platform for the treatment of pulmonary fibrosis and other oxidative stress-related diseases.（2）Regulation of V₄C₃-derived VO_xnanowires promoting oxidation activity and biomolecular detection.V₄C₃NSs was treated by temperature control oxidation method,and its micromorphology,electronic structure and valence state composition were characterized comprehensively.The morphology,structural composition and enzyme-like activities of the compounds were measured by SEM,TEM,XPS and UV-Vis.The results show that with the increase of oxidation degree,the nanosheets are broken by ion leaching and gradually regrown into VO_xnanowires composed of different valence states.Different oxidation temperatures mediated the growth of different dominant crystal surfaces,resulting in different morphologies and different POD activities of the products.Among them,oxidation at 40℃has the highest oxidation promoting activity,and the vanadium valence state is mainly stable at V³⁺,V⁴⁺and V⁵⁺.The POD activity of vanadium oxide nanoplates with mixed valence state is much higher than that of V₂O₅obtained by calcination,which proves that the valence engineering can achieve effective regulation of its enzyme activity.In addition,the high POD activity was applied to the colorimetric determination of dopamine and glutathione,and the results showed that the concentration of the target substance showed a good linear relationship in the range of 6.67μM-40μM（dopamine）and 1.67μM-13.33μM（glutathione）.