Highly water-dispersible PCN nanosheets as light-controlled lysosome self-promoting escape type non-cationic gene carriers for tumor therapy.

The construction of non-viral gene delivery faces two major challenges: cytotoxicity caused by high cationic charge units and easy degradation by lysosomes. Herein, highly water-dispersible polymeric carbon nitride (PCN) nanosheets were utilized as the core to construct a light-controlled non-cationic gene delivery system with sufficient lysosomal escape ability. In this system, these nanosheets exhibited efficient DNA condensation, outstanding biocompatibility, transfection tracking, light responsiveness and high transfection efficiency. Once PCN-DNA was taken up by the tumor cells, the accumulated ROS generated by photosensitizers (PSs) under light irradiation would destroy the structure of lysosomes, promote the escape of PCN-DNA and increase the efficiency of gene transfection. Simultaneously, the gene transfection process could be tracked in real time through fluorescence imaging technology, which was conducive to investigate the transfection mechanism. In vitro and in vivo experiments further confirmed that PCN nanosheets loaded with the P53 gene were beneficial to the regeneration of the P53 apoptotic pathway, increased tumor sensitivity to PSs, and further induced tumor cell apoptosis. In summary, the highly water-dispersible PCN nanosheets were applied to light-controlled self-escaping gene delivery for the first time, and tumor gene therapy was successfully realized.

Solid-state synthesis of single-phase nickel monophosphosulfide for the oxygen evolution reaction.

High-performance and cost-effective nonprecious-metal catalysts are essential for the next-generation oxygen evolution reaction (OER). However, the electrocatalysis of the OER during water splitting is often carried out by using noble metal catalysts, such as RuO2 or IrO2 with high-cost and limited stability. Herein, we reported a successful synthesis of a ternary nickel monophosphosulfide (NiPS) compound via a simple solid-state route and further investigated its electrocatalytic performances for water oxidation. It is found that the NiPS electrocatalyst exhibits good OER performance in 1.0 M KOH solution, i.e., achieving a current density of 20 mA cm-2 at an overpotential of 400 mV and a Tafel slope of 126 mV dec-1, comparable to commercial benchmark RuO2. The ternary NiPS electrocatalyst for the OER is superior to its binary counterparts, i.e., Ni2P and NiS. Density functional theory (DFT) calculations combined with ex situ XPS were performed to obtain further insights into the intrinsic catalytic mechanism of NiPS, and their results clearly revealed that the instability of the NiO intermediate during the OH* → O* process and the easy oxidation of the (PS)3- anion favoring the formation of hydroxyl-based species (i.e., Ni(OH)2/NiOOH) on the surface of the catalyst, which plays a crucial role in facilitating the OER activity. Furthermore, we creatively extended this method to the fabrication of heteroatom substituted catalysts and a new quaternary CoNiP2S2 compound was successfully synthesized for the first time in the same way. The structural properties and electrocatalytic performance towards the OER for CoNiP2S2 (e.g., 20 mA cm-2 at 376 mV) are also systematically investigated in this work.