Nano-drug Delivery System Co-delivery Doxorubicin And SiRNA Combined With Near-infrared Hyperthermia Based On Nano-Molybdenum Disulfide

OBJECTIVE: To prepare nano-molybdenum disulfide with nano-flake morphology,and to synthesize drug carriers with good stability and low cell cytotoxicity through further modification.To fabricate a drug delivery system based on nano-molybdenum disulfide for co-delivery of doxorubicin(DOX)and siRNA,which can be used for combined chemotherapy,gene therapy and photothermal therapy.METHODS: Molybdenum disulfide nanosheets were prepared by a hydrothermal reaction of ammonium molybdate and thiourea.Molybdenum disulfide nanosheets were modified by high molecular polymer(polyethyleneimine and polyethylene glycol)as drug carriers.The preparation of the drug carrier was characterized by transmission electron microscopy(TEM),X-ray photoelectron spectroscopy(XPS),Fourier transform infrared spectroscopy(FT-IR)and laser particle size potentiometer.The cytotoxicity of the drug carriers were determined by MTT assay using human normal hepatocyte HL-7702 cells and human breast adenocarcinoma MCF-7 cells as models,and the biocompatibility of drug carrier was preliminarily investigated.The absorption and conversion ability of the drug carrier to near infrared light was investigated by photothermal performance measurement.The loading and release behavior of drug carrier to DOX and the loading of siRNA were investigated to evaluate the Co-loading ability of drug carriers on DOX and siRNA.Human breast adenocarcinoma MCF-7 cells and drug-resistant breast adenocarcinoma cell MCF-7/Adr cells were used as examples to investigate the anti-tumor effect of the drug loading system.RESULTS: Molybdenum disulfide nanotsheets with a particle size of about 120 nm were successfully prepared and identified by TEM and XPS.Molybdenum disulfide nanocarrier with a particle size of about 135 nm and Zeta potential of about +20.5 mV were successfully constructed by PEI and PEG modification,and the modification process was confirmed by XPS and FT-IR.The cytotoxicity to HL-7702 cells and MCF-7 cells were determined by MTT assay with concentration ranging from 0.78 to 50.00 ?g/mL.After 24 hours of co-culture,cell viability was not affected,and the relative survival rate was above 80%,indicating that the drug carrier had good biocompatibility.Photothermal experiments showed that when the drug carrier was at a low concentration of 0.05mg/mL,it had obvious near-infrared photothermal absorption,and the temperature rose more than 30? after 10 minutes of light exposure.The calculated photothermal conversion efficiency is 21.9%.At the same time,the photothermal performance of the drug carrier was affected by the concentration of carrier and the laser power employed.The higher the concentration of carrier and the laser power used,the higher the photothermal conversion performance of the drug carrier.Drug loading experimentation showed that the drug carrier loaded about 900 mg DOX per g of drug carrier when the concentration of DOX was 1.0 mg/mL.Drug release experimentation found that the drug carrier loaded with DOX released 22% at 24 hours at 5.5 acidic pH of tumors,while the release rate was only 5% in 7.4 physiological pH environment.Thus,the release of DOX showed pH responsiveness.Under near infrared laser irradiation,the drug carrier loaded with DOX released 61.4% in 24 hours at 5.5 pH,while 24.0% at 7.4 pH.Thus,the release of DOX was responsive to near infrared laser.By agarose gel electrophoresis,it was found that the carrier loaded with DOX could further load siRNA and realize the co-delivery of DOX and siRNA.Preliminary studies on the anti-tumor activity of drug delivery system showed that the drug delivery system co-delivery with DOX and siRNA combined with near infrared laser irradiation at a concentration of 5.0 ?g/mL could achieve a higher anti-tumor effect on drug-resistant breast cancer cells than that of doxorubicin alone.The relative survival rate of cells was 55.18%.CONCLUSION: Molybdenum disulfide nanosheets can be prepared by hydrothermal reaction.The drug carrier has low cell cytotoxicity,excellent near infrared photothermal absorption,and can simultaneously load DOX and siRNA.Therefore,its use as a drug carrier has the potential to achieve combined chemotherapy,gene therapy and photothermal therapy.