Structural Regulation And Antibacterial And Antitumor Properties Ofmolybdenum Oxide Intercalated Nanomaterials

Life and health is one of the primary concerns of human beings.Bacterial infections and malignant tumors are two major factors that threaten human health.Therefore,the search for bactericidal and antitumor drugs with excellent performance has always been a hot research topic in the field of biomedicine.In recent years,due to the unique properties and functions of layered nanomaterials,it have been widely used in many fields such as material science,food safety testing,genetic engineering,biochemical engineering,enzyme engineering,and medicine.The researchers found that by modifying layered nanomaterials,functional nanomaterials with excellent performance can be obtained.Therefore,structural regulation and functional modification of layered nanomaterials are of great significance for the development of antibacterial and antitumor drugs.In the study,molybdenum oxide nanomaterials intercalated with sodium ions and a series of organic fluorescent molecules were obtained through design,synthesis and functional modification.Infrared spectroscopy（IR）,thermogravimetric analyzer（TG）,scanning electron microscope（SEM）,transmission electron microscope（TEM）,X-ray powder diffractometer（XRD）and X-ray photoelectron spectroscopy（XPS）and electron paramagnetic resonance spectroscopy（ESR）were used to characterize its structure and morphology.Further explore its properties and application process in the field of antibacterial and anti-tumor,the main research work is as follows:（1）Molybdenum trioxide nanoribbons（MoO₃）with uniform morphology were first prepared in large quantities by a classical hydrothermal method,and then sodium ions and water molecules were inserted between the layers of MoO₃in one step through the strategy of aqueous intercalation to obtain molybdenum oxide nanoribbons（Na⁺/H₂O-MoO₃）with co-intercalated sodium ions and water molecules rich in oxygen defects The materials before and after intercalation were characterized by TG,SEM,TEM,XRD,ESR and XPS,respectively.The results showed that compared with the blank MoO₃nanobelts,the Na⁺/H₂O-MoO_3-xnanobelts had wider interlayer spacing,abundant oxygen vacancies（OVs）and stronger optical absorption in the near-infrared region.The photothermal and photodynamic properties of molybdenum oxide nanoribbons before and after intercalation were further investigated in detail,and the results showed that Na⁺/H₂O-MoO_3-xnanoribbons could rapidly heat up and produce a large amount of nanoribbons under near-infrared light（808 nm）irradiation.The reactive oxygen species was proved to be superoxide anion（·O₂^-）by reactive oxygen probe technology and EPR method.Finally,we investigated the actual antibacterial properties of MoO₃and Na⁺/H₂O-MoO_3-xnanobelts,respectively,and found that MoO₃showed no obvious antibacterial effect.For Na⁺/H₂O-MoO_3-x,it can kill E.coli and S.aureus to a large extent after 10 min of illumination,indicating that it has excellent antibacterial properties and can be used as a potential photodynamic nanometer.（2）On the basis of the above research,in order to control the nano-size of the material to make it more useful in the application of biological system.We first use a ball mill by controlling the parameters such as ball milling time and ball milling frequency to reasonably obtain nano-sized MoO₃nanobelts（BM-MoO₃）.Then,using BM-MoO₃as the intercalation precursor,the nano-sized sodium ion and water molecule co-intercalation intermediate product(Na⁺/H₂O-MoO_3-x)was prepared by aqueous intercalation.In order to endow nanomaterials with bioimaging functions for early diagnosis of diseases,we selected a series of cationic fluorescent dyes（including:NB,TPE-I,TPA-I and PHC-I）.A series of cationic dye-intercalated molybdenum oxide-based nanomaterials were successfully synthesized by ion exchange between dyes and sodium ions(including:NB-MoO_3-x,TPE-I-MoO_3-x,TPA-I-MoO_3-xand PHC-I-MoO_3-x).By comparing the structure and morphology of a series of materials,it is found that the exchange of sodium ions between the organic dye molecules,the interlayer spacing of the materials will be further increased and OVs of the materials will be maintained.Therefore,under the premise of retaining the enzymatic catalytic performance of the material,it can successfully endow it with the function of fluorescence imaging.In addition,the bioenzyme-like catalytic performance of NB-MoO_3-xnanoparticles was studied by using a variety of ROS probes.The results showed that hydroxyl radicals（·OH）and superoxide anion（·O₂^-）could be generated when NB-MoO_3-xnanoparticles coexisted with H₂O₂,and has a significant pH dependence.To further improve the biocompatibility of NB-MoO_3-xnanoparticles,we modified them with polyvinylpyrrolidone（PVP）to obtain PVP@NB-MoO_3-x.The intracellular fluorescence imaging,ROS monitoring and cytotoxicity analysis were investigated.The results show that NB-MoO_3-xcan effectively perform fluorescence imaging on cells,and at pH 5.4,it interacts with intracellular hydrogen peroxide to generate a lot of ROS,which in turn causes oxidative damage to 4T1 cells.Finally,using mouse epidermal tumor as the research object,through in vivo fluorescence imaging,it was found that PVP@NB-MoO_3-xcan effectively accumulate in tumor tissues,and can effectively inhibit tumor growth without toxic side effects on biological tissues.In the study,the intercalation strategy was used to modulate the structure of molybdenum oxide nanomaterials,which provided a new method for the construction of novel inorganic nanobiomaterials.And further explored the application of intercalated materials in antibacterial and antitumor,providing theoretical basis and experimental support for understanding the antibacterial and antitumor mechanism of inorganic nanomaterials.