Preparation And Biomedical Applications Of Light-responsive Porous Core-shell Nanoparticles

In recent years,the construction of core-shell nanostructure is considered to be an effective method for developing multifunctional theranostic nano-platforms.The light-responsive porous core-shell nanoparticles not only have the advantages of temporal and spatial controllability from the light-responsive system,but also have the characteristics of nano-scale pore structure,large specific surface area and easy functionalization.Meanwhile,the two materials constituting the core and the shell may achieve complementary advantages,through reasonable selection,and even yield superadditive effect in performance.Therefore,nanosystems with light-sponsive cores and porous shells have received increasing attention in the field of biomedicine.Here,we develop two different types of theranostic nanosystems with light-sponsive cores and porous shells for cancer treatment and afterglow bioimaging,respectively.In the field of cancer treatment,multifunctional nanoplatforms are increasingly favored by researchers.And nanosystems capable of active movement tend to have higher anticancer effects as compared to passive counterparts.Thus,we synthesize a dual enzyme-functionalized core-shell nanomotor(designated as UTZCG)based on metal-organic framework nanoparticles for enhancing synergetic photodynamic therapy(PDT)and starvation therapy(ST).The modified glucose oxidase(GOx)catalyzes the decomposition of intracellular glucose,which starves cells and generates hydrogen peroxide(H2O2).Then,catalase-triggered decomposition of both endogenous and GOx-generated H2O2 provides propulsion force and enhances the diffusivity of the nanomotors by up to about 27%,which increases the cellular uptake of the therapeutic nanomotors.Meanwhile,the produced oxygen molecules not only promote singlet oxygen generation during near-infrared light-triggered PDT process,but also facilitate the GOx-triggered decomposition of glucose.Thus,the two enzymatic cascade reactions form a positive feedback for the whole nanomotor based therapeutic system,and greatly improve the efficacy of the synergetic PDT and ST.In the field of bioimaging,ultralong organic phosphors(UOP)have attracted attention because of their advantage of anti-background fluorescence interference.In view of the problems of the current ultralong organic phosphors such as poor hydrophilicity and large size,we provide a facile and versatile approach to obtain nanoscale hydrophilic phosphorescent phosphors.UOP are loaded into the cavities of the hollow mesoporous silica nanoparticles to form a core-shell structure by recrystallization of the UOP.The as-prepared hydrophilic phosphorescent phosphors can be well dispersed in aqueous solution and effectively internalized by He La cells with very low cytotoxicity.Additionally,the hydrophilic phosphorescent phosphors are applied for afterglow bioimaging in living nude mice with a high signal-to-noise ratio up to around 31,demonstrating their great potential for biomedical purpose as an advanced imaging indicator with long-lived emission lifetime.