The insufficient blood flow and oxygen supply in solid tumor cause hypoxia, which leads to low sensitivity of tumorous cells and thus causing poor treatment outcome. Here, mesoporous manganese dioxide (mMnO 2 ) with ultrasensitive biodegradability in a tumor microenvironment (TME) is grown on upconversion photodynamic nanoparticles for not only TME-enhanced bioimaging and drug release, but also for relieving tumor hypoxia, thereby markedly improving photodynamic therapy (PDT). In this nanoplatform, mesoporous silica coated upconversion nanoparticles (UCNPs@mSiO 2 ) with covalently loaded chlorin e6 are obtained as near-infrared light mediated PDT agents, and then a mMnO 2 shell is grown via a facile ultrasonic way. Because of its unique mesoporous structure, the obtained nanoplatform postmodified with polyethylene glycol can load the chemotherapeutic drug of doxorubicin (DOX). When used for antitumor application, the mMnO 2 degrades rapidly within the TME, releasing Mn 2+ ions, which couple with trimodal (upconversion luminescence, computed tomography (CT), and magnetic resonance imaging) imaging of UCNPs to perform a selfenhanced imaging. Significantly, the degradation of mMnO 2 shell brings an efficient DOX release, and relieve tumor hypoxia by simultaneously inducing decomposition of tumor endogenous H 2 O 2 and reduction of glutathione, thus achieving a highly potent chemo-photodynamic therapy.

No abstract

NIR light-induced imaging-guided cancer therapy is an encouraging route in the cancer theranostic field. Herein, we describe a novel nanoscale proposal, which is established by covalently implanting core-shell structured upconversion nanoparticles (UCNPs) with nanographene oxide (NGO) by a process utilizing polyethylene glycol (PEG), and consequently loading Chlorin e6 (Ce6) onto the surface of NGO. The acquired NGO-UCNP-Ce6 (NUC) nanocomposites can not only be employed as upconversion luminescence (UCL) imaging probes of cells and whole-body animals with high contrast for diagnosis, but also can generate reactive oxygen species (ROS) under 808 nm light excitation for photodynamic therapy (PDT); over and above, they can swiftly and proficiently translate the 808 nm photon into thermal energy for photothermal therapy (PTT). An extraordinarily enhanced and synchronized therapeutic effect paralleled to the individual PTT or PDT is achieved, rendering extraordinary therapeutic effectiveness for cancer treatment. Consequently, profiting from this inimitable multifunctional nanohybrid, the NUCs synthesized here are encouraging as a cohesive theranostic probe for impending UCL imaging-guided combinatorial PDT/PTT.