IR780 And Polydopamine Encapsulated In Biodegradable PLGA Nanoparticles For Photothermal And Photodynamic Therapy Of Bladder Cancer

Objective The PLGA-coated IR780 and polydopamine(PDA)constitute a two-drug nano-delivery system,which synergistically enhances photothermal and photodynamic effects to treat bladder cancer.(1)To prepare and characterize PLGA-IR780-PDA NPs;(2)To evaluate the killing effects of PLGA-IR780-PDA nanoparticles against mouse MB49 cells in vitro.Methods(1)PLGA-IR780-PDA NPs were prepared and characterized:PLGA-IR780-PDA NPs were prepared by nano-sinking method.Inner layer:15 ml aqueous solution and 0.15 mg PEG buffer;intermediate layer:acetonitrile solution was set to 5 mg/ml PLGA and 1 mg/ml IR780 mixture;external aqueous phase:100 mg/ml PDA.After sufficient shaking,mixing and centrifuging,PLGA-IR780-PDA NPs were obtained.The nanoparticle size was measured by laser particle size analyzer.The size and morphology of the nanoparticles were observed by electron microscope.The temperature of the nanoparticle solution after laser excitation was recorded by infrared thermometer.(2)In vitro cytotoxicity of PLGA-IR780-PDA NPs against mouse MB49 cells:MTT assay was used to detect the killing of the constructed nanoparticle system,Hoechst staining was used to detect living cells,and Tunnel staining was used to detect apoptosis.Flow cytometry was used to detect cell cycle,and WB assay was used to analyze the expression of apoptosis proteins.Results(1)PLGA-IR780-PDA NPs have a particle size of 156 nm and a drug loading rate of 1.7%.It exhibits a typical spherical shape,round shape and good dispersion under an electron microscope.The temperature of PLGA-IR780(60μg/ml)-PDA NPs group increased to 45 ℃ after 10 minutes of laser irradiation.(2)MTT test proved that The OD values of PLGA-IR780 NPs,PLGA-PDA NPs and the PLGA-IR780-PDA NPs groups were significantly lower than those of the Control group(P<0.05),and the OD values of the PLGA-IR780 NPs group was more lower than the PLGA-IR780-PDA NPs group with no statistical significance.Conclusion(1)We have successfully constructed PLGA-IR780-PDA NPs.The optimized size of the nanoparticles prepared and the drug loading is good and the dispersibility is good.(2)PLGA-IR780-PDA NPs enhance the photothermal and photodynamic effect to kill MB49 tumor cells and reduce biological toxicity of IR780.