Synthesis And Morphology Control Of MoO_3-x Nanomaterials For Phothermal Therapy Of Cancer

As one of the killers of human health,cancer has become a focus in the field of biomedicine.Surgery,radiotherapy,and chemotherapy are the three major treatments to cure cancer,but they can cause great damage to the human body and bring about other complications.Near infrared light?NIR?-mediated photothermal therapy with strong penetrating power and small tissue damage has attracted much attention.Conventional photothermal agents limited by the cumbersome preparation process,high cost,insufficient light stability and poor biocompatibility are difficult to apply in photothermal therapy.Oxygen-deficient molybdenum oxide(MoO_3-x)as one of photothermal therapeutic nanomaterials,they both have high photothermal conversion efficiency and unique physical and chemical properties are applied in vivo imaging,biochemical sensing,drug determination,immunoanalysis,Gene detection,photothermal therapy and other aspects.However,MoO_3-x nanomaterials are usually prepared with cumbersome and required further surface modification to be applied to biological systems.Moreover,the photothermal conversion rates of MoO_3-x nanomaterials is also lower than that of noble metals.In view of the above problems,MoO_3-x QDs and MoO₂ nanospheres with stable and high photothermal conversion efficiency synthesized by UV irradiation method and one-step hydrothermal method respectively.The specific content includes the following two parts:?1?MoO_3-x QDs were successfully obtained by ultraviolet irradiation with ammonium molybdate(?NH₄?₆Mo₇O₂₄·4H₂O)as the molybdenum source and PVP as the reducing agent.In the course of the experiment,we explored the amount of PVP,the reaction time and whether?NH₄?₆Mo₇O₂₄·4H₂O can be used as a single raw material to form oxygen-defective molybdenum oxide,and TEM,HRTEM,XRD,FT-IR,XPS were used to characterize afterward.At the same time,MoO_3-x QDs with absorption peaks in the near-infrared region?NIR?detected by UV-visible absorption spectroscopy,and the position of the absorption peak can be adjusted by regulating the amount of PVP.According to the characteristics of NIR absorption,MoO_3-x QDs can effectively convert808 nm laser energy into heat energy,and the conversion efficiency is determined to be 40.01%.The cytotoxicity subsequently examined for further application in photothermal therapy.When the concentration of MoO_3-x QDs was 3 mg/mL,the cell viability decreased by 10.6%after irradiation with 808 nm laser,indicating that it has potential as a photothermal reagent.Further,we have also found that MoO_3-x QDs have the potential to be used as glucose sensors.The release of hydrogen peroxide by glucose oxidase and the change of NIR absorption during hydrogen peroxide oxidation of MoO_3-x QDs were used as the basis for selective glucose detection.The detection limit was 10?M.?2?Using?NH₄?₆Mo₇O₂₄·4H₂O as the molybdenum source and PVP as the reducing agent,the MoO_3-x nanomaterials were prepared by one-step hydrothermal method.With the increase of reaction temperature,the morphology of MoO_3-x nanomaterials changed from amorphous to crystalline,while MoO_3-x nanomaterials showed a gradual enhanced localized surface plasmon resonance?LSPR?effect in the near-infrared region.Among them,MoO₂ nanospheres have the strongest absorption peak in the NIR region,and the photothermal conversion efficiency is as high as 72.5%after 808 nm near-infrared laser irradiation.In addition,the toxicity and photothermal treatment effects of MoO₂ nanospheres were measured systematically in vitro and in vivo.The results showed that MoO₂ nanospheres had low cytotoxicity and no obvious damage to tissues and organs,indicating that they could be applied in photothermal therapy.This opens up new possibilities for the development of PTT formulations in the biomedical field.