Synthesis Of Magnetic Element Doped Molybdenum Oxide Nano-photothermal Reagent And Its Application In Tumor Treatment

In recent years,the incidence of cancer has increased.Photothermal therapy has the characteristics of minimal invasiveness,low side effects,and high efficiency.It has gradually attracted widespread attention as a new treatment method.Photothermal therapy uses photothermal agents(PTAs)to absorb near-infrared(NIR)light to convert light energy into heat energy,which generates high heat locally to kill tumor cells.Therefore,the premise of photothermal therapy is to develop photothermal reagents with good photothermal performance.Because water and blood cells absorb very little near-infrared light,which allows light to penetrate deep tissues to excite PTAs,and minimize damage to nearby healthy tissues,PTAs need to have strong light absorption in the near-infrared region.Currently,the most researched PTAs are semiconductor nanomaterials,precious metals,carbon-based materials,organics,etc.In comparison,semiconductor nanomaterials have the advantages of low cost,low price,and better absorption in the near infrared region.As an essential trace element for humans and mammals,molybdenum is also a cofactor for various enzymes,such as sulfite oxidase,aldehyde oxidase and xanthine oxidase.The lack of molybdenum in the diet can increase the incidence of esophageal cancer;Hexavalent molybdenum complex is also an effective anti-diabetic drug.In recent years,molybdenum oxide-based materials have been widely used in nanomedicine fields,such as biocatalysis,antibacterial,and cancer treatment.Therefore,molybdenum-based oxides have great potential in biological applications.Based on this,this paper designed and prepared magnetic element doped molybdenum oxide-based photothermal conversion materials,and systematically studied its photothermal performance and its application in tumor treatment:(1)Synthesis of Fe-doped MoO_x nanowires and its application in tumor treatmentIntegrating multiple functions such as photothermal and magnetic imaging on a single nanomaterial can effectively improve the effect of tumor treatment and reduce excessive treatment.In this chapter,by incorporating Fe element into MoO_x,on the one hand,more defects are produced and the photothermal performance is improved;on the other hand,the introduction of Fe element gives the material excellent catalytic performance and nuclear magnetic imaging function.Fe-doped MoO_x can effectively improve the photothermal conversion performance of the material,and efficiently kill tumor cells;Fe-doped MoO_x catalyzes H₂O₂ generation in the cell to kill tumor cells,and the photothermal effect can also be enhanced the generation of reactive oxygen species has the effect of synergistic treatment of tumors.In addition,the high photothermal performance of Fe-doped MoO_x can effectively ablate tumors in mice,and at the same time generate T1-enhanced MRI signals at the tumor site,which will gradually degrade in the physiological environment without affecting normal tissues.In order to study the long-term toxicity of the material to mice,Fe-doped MoO_x was injected through the tail vein,and the biodistribution of the material in the mouse body and tissue sections were analyzed,which proved that Fe-doped MoO_x has high biological safety.In summary,Fe-doped MoO_x can be used as a multifunctional and efficient new photothermal reagent for effective treatment of tumors.(2)Synthesis of Co,Ni-doped MoO₂ nanomaterials and their photothermal performanceMolybdenum dioxide(MoO₂)is a twisted rutile structure with the advantages of low resistivity,good chemical stability,and strong near-infrared absorption.It is an attractive transition metal oxide bioapplied materials.However,MoO₂ has low photothermal conversion efficiency in the near-infrared region,and the synthesized MoO₂ has poor water solubility and poor biocompatibility.These problems need to be solved to better use MoO₂ in biological applications.In this chapter,through the doping of Ni and Co,Ni-doped MoO₂ and Co-doped MoO₂ nanoparticles are prepared,which have good dispersibility in aqueous solution,and have a high photothermal conversion efficiency at 808 nm(42.3%and 49.1%respectively).In the cell experiment,the material showed good biocompatibility.At a concentration of 200?g m L^-1,the cell survival rate was still above 80%,which has high biological safety.Under 808 nm laser irradiation,it can effectively kill tumor cells.