Local hypoxia in tumors results in undesirable impediments for the efficiencies of oxygen‐dependent chemical and photodynamic therapy (PDT). Herein, a versatile oxygen‐generating and pH‐responsive nanoplatform is developed by loading MnO2 nanodots onto the nanosystem that encapsulates g‐C3N4 and doxorubicin hydrochloride to overcome the hypoxia‐caused resistance in cancer therapy. The loaded MnO2 nanodots can react with endogenous acidic H2O2 to elevate the dissolved oxygen concentration, leading to considerably enhanced cancer therapy efficacy. As such, the as‐prepared nanoplatform with excellent dispersibility and satisfactory biocompatibility can sustainably increase the oxygen concentration and rapidly release the encapsulated drugs in acid H2O2 environment. In vitro cytotoxicity experiments show a higher therapy effect by the designed nanoplatform, when compared to therapy without MnO2 nanodots under hypoxia condition, or chemical and photodynamic therapy alone with the presence of MnO2 nanodots. In vivo experiments also demonstrate that 4T1 tumors can be very efficiently eliminated by the designed nanoplatform under light irradiation. These results highlight that the MnO2 nanodots‐based nanoplatform is promising for elevating the oxygen level in tumor microenvironments to overcome hypoxia limitations for high‐performance cancer therapy.
The damage of optic nerve will cause permanent visual field loss and irreversible ocular diseases, such as glaucoma. The damage of optic nerve is mainly derived from the atrophy, apoptosis or death of retinal ganglion cells (RGCs). Though some progress has been achieved on electronic retinal implants that can electrically stimulate undamaged parts of RGCs or retina to transfer signals, stimulated self-repair/regeneration of RGCs has not been realized yet. The key challenge for development of electrically stimulated regeneration of RGCs is the selection of stimulation electrodes with a sufficient safe charge injection limit (Q(inj), i.e., electrochemical capacitance). Most traditional electrodes tend to have low Q(inj) values. Herein, we synthesized polypyrrole functionalized graphene (PPy-G) via a facile but efficient polymerization-enhanced ball milling method for the first time. This technique could not only efficiently introduce electron-acceptor nitrogen to enhance capacitance, but also remain a conductive platform-the π-π conjugated carbon plane for charge transportation. PPy-G based aligned nanofibers were subsequently fabricated for guided growth and electrical stimulation (ES) of RGCs. Significantly enhanced viability, neurite outgrowth and antiaging ability of RGCs were observed after ES, suggesting possibilities for regeneration of optic nerve via ES on the suitable nanoelectrodes.
In recent, the quantum yield (QY) and stability of green quantum dots (QDs) have been significantly improved. However, most of the progresses were achieved by using alloyed QDs, and the control of green emission QDs still remains challenging. Herein, we report a novel method for synthesizing thick-shell structure quantum dots (TSQDs) with saturated green-emitting where tri-n-octylphosphine (TOP) was used as both ligand
and
solvent to extract the redundant ions from the QDs surface and remove the lattice imperfections before any surface inorganic layer-by-layer coating. The as-prepared TSQDs demonstrate enhanced luminescent properties including high QY reaching up to 75%, full width at half maximum (FWHM) remaining close to 26 nm and tunable precise emission properties (532 nm), which can be utilized to perform 91% of the International Telecommunication Union (ITU) Recommendation BT. 2020 (Rec. 2020) for high definition and color gamut displays.
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