Construction Of NIR Triggered ROS Sensitive?UCN@SiO₂-RB+Dox?@PPADT Nanoparticles For Simultaneous Chemotherapy And Photodynamic Therapy

In recent years,the combined therapy may play a major role in cancer therapy.However,the previous systems may be unable to achieve simultaneous therapy effects of several methods.To solve the problem,we constructed a delivery system of near-infrared light(NIR)triggered reactive oxygen species(ROS)sensitive nanoparticles for simultaneous chemotherapy and photodynamic therapy.The inner nanoparticle was assembled from the hydrophobic upconverting nanoparticle(UCNs)core,the thin silica shell linked with the rose bengal(RB).Finally,a type of ROS-induced biodegradable polymer named poly-(1,4-phenyleneacetone dimethylenethioketal)(PPADT)was self-assembled to form the nanoparticle as outer shell loaded the inner nanoparticle and doxorubicin(DOX).As the results show,the UCN core works as a transducer to convert deeply penetrating near infrared light to visible light for activating the photosensitizer RB for photodynamic therapy(PDT)under NIR excitation.And in the meantime,the redundant ROS could cause PPADT to biodegrade to release the loaded DOX,realizing the simultaneous chemotherapy and photodynamic therapy.The properties such as structure,size distribution,morphology,FTIR,ROS production test,cell uptake test and combined therapy treatment effect in vitro were evaluated to prove NIR triggered ROS sensitive(UCN@SiO2-RB + DOX)@PPADT nanoparticles.To evaluate the structure and property of the(UCN@SiO2@-RB+DOX)@PPADT for simultaneous chemotherapy and PDT treatment,some effective characterization methods were used.The TEM images,EDS spectrum and FTIR can show the morphology of the delivery system and the 1HNMR and GPC data suggest success of synthesis and ROS-biodegradation about PPADT.The ROS production test and PDT test suggest that the fluorescence emitted from the UCNs excited by NIR can effectively activate RB to generate cytotoxic ROS and in vitro drug release test shows effective PPADT biodegradation to cause controlled drug release.Based on our data,this delivery system could provide an effective mean to realize simultaneous chemotherapy and PDT through external NIR triggered ROS sensitivity.