Construction Of Reactive Oxygen-responsive Molybdenum Disulfide Phototherapy Nanocarriers And Antimicrobial Wound Healing Promotion Study

Drug-resistant bacterial infections are a serious threat to human survival and health.Wound infections with drug-resistant bacteria may lead to long-term debilitation of patients and increase medical costs.Due to biofilm formation,traditional antibiotic treatments are no longer effective in killing drug-resistant bacteria.Therefore,new treatments are particularly important.The main research contents and results are as follows.（1）MoS₂ nanospheres of uniform size were synthesized by hydrothermal method,and a layer of MnO₂ nanoparticles was deposited on their surface by redox reaction and electrostatic adsorption as a carrier.Thereafter,AIPH was loaded by electrostatic adsorption to form MoS₂/MnO₂-AIPH nanocomposites（MMA）.Finally,polyethylene glycol diacrylate（PEGDA）was added to polymerize MoS₂/MnO₂-AIPH hydrogel（Gel（MMA））with the assistance of light for further application in wound healing.The size of MoS₂ nanospheres was observed to be around 180 nm by SEM and increased to 200 nm after loading with MnO₂and AIPH.UV,FT-IR,Zeta,XPS and other characterization methods confirmed the successful synthesis of MMA.The photothermal performance test showed that MMA has good and stable photothermal conversion efficiency up to 40.5%.The chemodynamic performance test showed that MnO₂ in MMA can deplete GSH and reduce the self-protection ability of bacterial cells.Meanwhile,^·OH is produced during the chemodynamic process,which further enhances the antibacterial performance.The minimum inhibitory concentration（MIC）results showed that MMA has the effect of inhibiting bacterial growth even at a low concentration of 38μg/m L.In vitro inhibition experiments showed that MMA（100μg/m L）under NIR light irradiation（2 W/cm²,5 min）achieved a biofilm ablation rate of over 90%and bacterial inhibition rate of over 96%.In addition,single-factor experiments showed that the synergistic effect factor（SEF）of the two treatments was greater than 0and the synergy coefficient（T/E）was greater than 1,indicating a significant synergistic effect of the materials.In mouse wound healing experiments,it was shown that the Gel（MMA）+NIR group could effectively promote wound healing,and the relative wound area was reduced to 30.4%after 8 days of treatment.（2）In order to further enhance the photothermal effect of the material,MoS₂ nanoflowers were chosen to replace the existing nanospheres.In addition,polydopamine（PDA）was chosen to attach to the surface of the nanoflowers.PDA not only acts as an adhesive to adsorb photosensitizers,but also PDA itself has a photothermal effect to enhance the photothermal ability of the material.Then indocyanine green（ICG）is introduced to give the material the ability to generate reactive oxygen species.The final nanocomposite of PDA/MoS₂-ICG is formed.It can be combined with photothermal and photodynamic therapy for antimicrobial activity.The successful synthesis of the materials was confirmed by SEM,FT-IR,UV-vis,and Zeta characterization.Photothermal performance experiments showed that the material has efficient photothermal effect with a photothermal conversion capacity of45.2%.Photodynamic experiments detected a large green fluorescence,indicating that the material produced reactive oxygen species.In vitro bacterial inhibition tests（MIC,CFU,etc.tests）showed that the nanocomposite of PDA/MoS₂-ICG（100μg/m L）achieved more than 97%bacterial inhibition under NIR light irradiation（1.5 W/cm²,5 min）.In addition,single-factor experiments showed that the synergistic effect factor（SEF）of the two treatments was greater than 0 and the synergy coefficient（T/E）was greater than 1,indicating a significant synergistic effect of the materials.In summary,based on the high GSH,oxygen-depleted microenvironment of biofilm,we designed the MoS₂ nano-drug delivery system.The MoS₂ nano-drug delivery system is effective and safe,and holds significant promise for clinical treatment of bacterial infections,ablation of biofilms and promotion of wound healing.