Folate-targeted Co-delivery Polymersomes Against Breast Cancer And Evaluation In Vivo Via OCTA/NIRF Dual-modal Imaging

Objective:Nanocarriers provide a co-loading platform for local and systemic antitumor therapy,effectively alleviating the disadvantages of strong side effects,poor stability and poor targeted aggregation of single therapy.That enhances the antitumor efficacy of combination therapy.In this study,we investigated the combination therapy against breast cancer and in vivo evaluation via optical coherence tomography angiography(OCTA)and near-infrared fluorescence imaging(NIRF),which provided real-time noninvasive evaluation of angiogenesis and antitumor efficacy for nanoparticles.Methods:(1)FA-MIT-SIPS were prepared by thin-film hydration method.The characterizations of nanoparticles including diameter,potential,dispersion(PDI),morphology,stability and drug loading were analyzed by instruments.The rate of cumulative drug release under different conditions was detected by high performance liquid chromatography.(2)The photothermal effect of nanoparticles was recorded by the infrared thermal imager,which screened the best optical power and photothermal drug concentration.Thermal cycling(10 min,4 times)was used to analyze the photothermal stability of the nanoparticles.OCT Optical signals of FA-MIT-SIPS with different concentrations,different flow rates and different temperatures were analyzed through simulated vascular in vitro.(3)The inhibitory effect of nanoparticles and free drugs on the activity of breast cancer cells was detected by MTS method to choose the best equivalent drug concentration.Based on the optical parameters and equivalent drug concentration,the drug uptake capacity of 4T1 cells was analyzed by confocal microscopy(CLSM)and flow cytometry(FACS)to analyze the drug uptake differences of different nanoparticles.FACS was used to quantitatively analyze the intracellular reactive oxygen species(ROS)during PDT treatment.(4)Breast cancer cells were inoculated to female BALB/C model subcutaneously and the suspension of nanoparticles was injected into the tail vein.The half life of nanoparticles was quantitatively analyzed by NIRF.The antitumor efficacy and vascular inhibition of FA-MIT-SIPS were evaluated by tumor volume,section staining and OCTA technique.The biosafety of nanoparticles was detected by organ pathology section and model weight.Results:(1)The diameter of FA-MIT-SIPS was 206 nm.The potential was-15.87 mV,which of PDI was 0.28.It indicated that the nanoparticles were small,good dispersion and perfect adsorption.According to the standard curve of drugs,DL of ICG,SOR and MIT was 83.16%,68.24%and 12%,respectively.The thermal cycle diagram of FA-MIT-SIPS was better than free drugs,indicating nanoparticles had good thermal stability.(2)With the increasing of its concentration,the light scattering characteristics of OCT image were enhanced(p<0.01).The photothermal effect destroyed the structure of nanoparticles under laser irradiation,the results of which was optical signal was weakened(p<0.05).OCT provided a real-time and convenient detection method for controlled release of drugs.(3)The trimodal synergistic effect of FA-MIT-SIPS inhibited the proliferation of 4T1 cells(p<0.001).Folate-modified nanopolysome enhanced cellular uptake.The mechanism of tumor cell apoptosis was triggered under laser irradiation.(4)The fluorescence intensity of ICG in FA-MIT-SIP was higher than free ICG,which indicated nanoparticles improved the half-life of drugs in vivo.As a result,the tumor cure rate increased to 40%.Histopathological sections showed that the nuclei and cytoplasm were separated.Large area of inflammatory infiltration and necrosis was infiltrated.H&E staining and weight curve showed that the nanoparticles had good biosafety.(5)The imaging of OCTA indicated density of vascular network around tumor decreased during treatment,which was consistent with anatomical information.The trimodal synergistic therapy effectively inhibited tumor angiogenesis and tumor growth.Conclusion:In this study,polymersomes were regarded as co-loading platform to realize the trimodal synergistic effect for breast cancer with chemotherapy,photothermal therapy,photodynamic therapy and anti-angiogenesis.Low pH response and photothermal effect promoted drug release and cellular uptake.FA-MIT-SIPS had good antitumor effect.OCTA/NIRF,dual-mode noninvasive imaging,provides quantitative indicators for antitumor angiogenesis and antitumor efficacy for FA-MIT-SIPS in vivo.This study provided reference and basis for trimodal synergistic effect,and promoted the application of OCT imaging technology in medical research.