Targeted Photothermal Effect Of Aptamer Modified MoS₂ Nanosheets

Cancer is a fatal disease that seriously threatens human health and life.How to effectively treat cancer has always been a difficult issue for the medical community.In recent years,near-infrared laser-induced tumor photothermal therapy has attracted widespread attention.Because near-infrared light has good tissue permeability,it can cause the photothermal effect enriched in the photothermal material at the tumor site to clear the tumor tissue.Therefore,photothermal therapy is expected to develop into a precise cancer treatment.MoS2 is one of the most studied photothermal materials in transition metal sulfides.Its unique band gap width,near-infrared absorption performance,light-to-heat conversion performance,and good biocompatibility make MoS₂ has potential application prospects in the field of tumor photothermal treatment.However,highly specific identification of MoS2 and effective enrichment of MoS2 nanosheets to tumor tissues to reduce the potential toxicity of nanomaterials is still a key issue that needs to be addressed in tumor photothermal treatment research and clinical translation.This paper starts from the above key issues,using nucleic acid aptamers to specifically identify target cells,and combining MoS2 nanosheets to adsorb bovine serum albumin to improve its biocompatibility,and controlling the size of MoS₂ nanosheets to reduce their toxicity.The targeted photothermal effects of aptamer-modified MoS₂ nanosheets have been studied.The main studies are as follows:?1?Construction and characterization of functionalized M0S2 nanosheetsIn this paper,MoS₂-BSA nanosheets were constructed by one-step hydrothermal synthesis and assisted ultrasonic stripping.MoS₂-BSA-Apt nanosheets were prepared by coupling nucleic acid aptamers to MoS₂-BSA through EDC/NHS chemical cross-linking.TEM,THTEM,XRD,Fourier transform infrared spectroscopy,ultraviolet-visible-near,hydration ppaper size,Zata potential,and suspension stability experimental characterization results show that MoS₂-BSA nanosheets contain more MoS₂ than MoS₂-BSA-Apt nanosheets,and MoS₂ has a particle size of 10 nm.Both solutions have heating-cooling,suspension stability,and near-infrared absorption characteristics.Infrared thermal imaging temperature monitoring results show that after the MoS₂-BSA and MoS₂-BSA-Apt nanosheets were irradiated by the laser with a wavelength of 808 nm,both functional MoS₂materials experienced a significant temperature rise,which had better photothermal effects.?2?Cytotoxicity and photothermal performance of tumor cell in vitro of functionalized MoS₂ nanosheetsAfter the functionalized MoS₂ nanosheets and MCF-7 human breast cancer cells were cultured in vitro,MTT experiments,photothermal effects,intracellular and extracellular singlet oxygen and membrane potential measurements were used to study the cytotoxicity of functionalized MoS₂ nanosheets and the photothermal properties of tumor cells in vitro.The experimental results show that MoS2-BSA and MoS2-BSA-Apt nanosheets have no obvious toxicity to the cells,both functionalized MoS2 nanosheets have good photothermal effects on tumor cells in vitro,but these two functionalized MoS2 nanosheets exhibit different photothermal effects;MoS2-BSA-Apt nanosheets can specifically recognize target cells and be transported into them.Photothermal treatment is accompanied by singlet oxygen production and cell mitochondria damage,which causes rapid apoptosis of tumor cells;while MoS2-BSA nanosheets are outside the cell,and the photothermal process also generates singlet oxygen.?3?In vivo photothermal treatment of functionalized MoS2 nanosheetsBased on the human breast cancer-bearing mice constructed in this paper,the effects of 808 nm laser on intratumoral injection of MoS2-BSA and tail vein injection of MoS2-BSA-Apt on the photothermal effect of mouse breast cancer cells and the pathway of MoS2 metabolism were studied.The experimental results show that,for the mice injected with MoS₂-BSA-Apt in the tail vein,all breast tumors disappeared after 14 days of photothermal treatment;and for the mice injected with MoS₂-BSA in the tumor,the growth of breast cancer tumors was suppressed,but did not completely disappear,and it has a tendency to rebound.Functionalized MoS2 nanosheets showed a steady increase in body weight during photothermal treatment for tumor-bearing mice in vivo.MoS₂ nanosheets had little effect on the five major organ tissues of the mouse heart,liver,spleen,lung and kidney.MoS2 nanosheets are mainly metabolized by the liver and spleen in the mouse hall.MoS2 nanosheets are basically metabolized and excreted 7 days after injection.Therefore,MoS₂-BSA-Apt can specifically recognize target cells.It has low toxicity,good biocompatibility,and photothermal properties.It is expected to be used in precise tumor treatment.