Synthesis Of MoS₂@ Carbon Nanomaterials And Study On The Characteristics Of Tumor Thermo-Chemotherapy

Traditional chemotherapy is usually the main treatment method for advanced cancer or the auxiliary method for early cancer surgery.Due to the non-specific cytotoxicity of chemotherapy drugs on cancer cells and normal cells,it usually leads to severe systemic toxicity.However,the results of chemotherapy are often limited by safe doses,resulting in insufficient drug concentration at the tumor site;and drug resistance may occur during treatment,which further hinders the overall efficacy.Therefore,it is urgent to improve the specific administration to reduce adverse reactions and optimize the therapeutic effect of low-tolerated doses.The combination of chemotherapy and hyperthermia in clinical practice improves the efficacy while targeting high-permeability and retention（EPR）effects to target specific drug delivery,increase the concentration of drugs at specific sites,improve drug specificity,and reduce toxicity.It is a worthy cancer treatment.At present,near-infrared photothermal therapy has the advantages of strong thermal ablation ability,minimally invasive and has become a powerful method for treating cancer.Nanomaterials with thermal effects that can absorb near-infrared light are used as chemotherapy drug carriers to achieve thermal triggering of drug release,and at the same time induce hyperthermia to produce synergistic anticancer effects at the same time.In this paper,using carbon-based nanomaterials as the matrix,MoS₂@C nanomaterials were first prepared.The excellent photothermal effect of MoS₂combined with the green and non-toxic carbon nanospheres for drug delivery.Not only shortens the irradiation time of near-infrared light,but also kills cancer cells within 3 minutes,thus avoiding damage to normal cells by prolonged exposure.Moreover,near infrared light irradiation and p H dual-response drug release are achieved to achieve the purpose of efficient and rapid photothermal-chemotherapy cooperative treatment.Second,the preparation of C@SiO₂ nanomaterials also established a dual-response drug delivery system.Based on the above,MoS₂/C@SiO₂ nanomaterials were prepared to optimize the lack of C@SiO₂ photothermal properties,and at the same time improve the drug-loading and drug-releasing capabilities.In short,the system provides the basis for the combined photothermo-chemotherapy.The main tasks as follows:（1）Preparation of MoS₂@C composite nanomaterials and its photothermal,cytotoxicity studies.Orthogonal experiments were used to optimize the conditions of the MoS₂@C composite nanomaterials synthesized by hydrothermal method,and PEG surface modification was carried out.The material’s crystal phase composition,morphology,light absorption characteristics,light and thermal properties,drug loading rate were characterized.The standard MTT method was used to determine the effect of nanocomposites on the survival rate of MCF-7 cells,and the anti-cancer activity of the materials was evaluated.The experimental results show that:the photothermal conversion efficiency of MoS₂@C is 40.8%and the drug loading rate is 44.37%under the best synthesis conditions;the photothermal conversion efficiency of PEG-MoS₂@C after surface modification of PEG is reduced by 20.24%,but the drug loading rate significantly improved,reaching 52.34%.PEG-MoS₂@C-DOX can achieve a drug release rate of 74.9%in a tumor microenvironment at p H 5.0 and 808 nm near-infrared light irradiation.The material has stable photothermal properties and good biocompatibility.Cytotoxicity experiments showed that under near-infrared light irradiation,the killing rates of MoS₂@C on tumor cells before and after drug loading were 57.33%and 73.4%,respectively.It can be seen that this nanomaterial can achieve photothermal-chemotherapy collaboration in tumor diagnosis and treatment treatment.In addition,the antibacterial experiment proved that the material is also a good antibacterial material.（2）Preparation of C@SiO₂ composite nanomaterials and its photothermal,cytotoxicity studies.The C@SiO₂ nanomaterials synthesized by the orthogonal experiment hydrothermal method were optimized,and the surface was modified by HF etching.The experimental results show that the photothermal conversion efficiency of C@SiO₂ is 34.7%under the optimal synthesis conditions,and the drug loading rate is 12.4%;after HF etching,the drug loading rate of HF-C@SiO₂ is significantly increased,up to 26.3%.The drug release rate of C@SiO₂-DOX in the tumor microenvironment at p H 5.0 and 808 nm near-infrared light irradiation can reach 35.8%.The material has stable photothermal properties and good biocompatibility.Cytotoxicity experiments showed that under the irradiation of near infrared light,the killing rate of C@SiO₂ on tumor cells before and after drug loading was 34%and 75.33%,respectively.It can be seen that this nanomaterial can achieve photothermal-chemotherapy collaboration in tumor diagnosis and treatment treatment.（3）Preparation of MoS₂/C@SiO₂ composite nanomaterials and their photothermal,cytotoxicity studies.Experiments show that the photothermal conversion efficiency of C@SiO₂ is 42.5%,and the drug loading rate is 46.5%;the drug release rate of C@SiO₂-DOX in the tumor microenvironment at p H 5.0and 808 nm near-infrared light irradiation can reach 58.9%,2.5 times the release rate without irradiation.The material has stable photothermal properties and good biocompatibility.Cytotoxicity experiments showed that under the irradiation of near infrared light,the killing rate of MoS₂/C@SiO₂ on tumor cells before and after drug loading was 46%and 80.6%,respectively.It can be seen that the nano-material can realize photothermal-chemotherapy cooperative treatment in tumor diagnosis and treatment.