Dual-Responsive Triple-Synergistic Fe-MOF for Tumor Theranostics.

The intelligent responsive drug delivery system has great application potential in cancer precision therapy. Although many antitumor methods have been developed based on drug delivery systems, most of them yet suffer from poor antitumor efficiency. In this project, a near-infrared and pH dual-response multimodal collaborative platform for diagnosis and treatment (PCN-DOX@PDA) was constructed. We used PCN-600 as a vehicle loaded with antineoplastic drugs and polydopamine (PDA). Under 633 nm laser irradiation, the ligand tetrakis(4-carboxyphenyl)porphyrin (TCPP) in PCN-600 can generate singlet oxygen (1O2) and kill tumor cells. PDA is used as photothermal agent of PTT. PCN-DOX@PDA achieves the intelligent release of antitumor drugs by responding to the weak acidity of the tumor microenvironment and thermal stimulation generated by NIR irradiation. In addition, since the central ion of PCN is Fe3+, PCN-DOX@PDA realizes the diagnosis and treatment of tumors through magnetic resonance imaging-mediated tumor chemotherapy and photothermal and photodynamic synergistic therapy. This triple synergistic strategy showed excellent biocompatibility and antitumor ability in in vivo experiments on a 4T1 tumor-bearing mouse model, indicating that PCN-DOX@PDA has a good development prospect in the field of precision cancer therapy and diversified biomedical applications.

Antibacterial Cascade Catalytic Glutathione-Depleting MOF Nanoreactors.

Nanozymes with peroxidase-like activity have great application potential in combating pathogenic bacterial infections and are expected to become an alternative to antibiotics. However, the near-neutral pH and high glutathione (GSH) levels in the bacterial infection microenvironment severely limit their applications in antibacterial therapy. In this work, a metal-organic framework (MOF)-based cascade catalytic glutathione-depleting system named MnFe2O4@MIL/Au&GOx (MMAG) was constructed. The MMAG cascade-catalyzed glucose to provide H+ and produces a large amount of toxic reactive oxygen species. In addition, MMAG consumed GSH, which can result in bacterial death more easily. Systematic antibacterial experiments illustrated that MMAG has superior antibacterial effects on both Gram-positive bacteria and Gram-negative bacteria.

Three-dimensional graphene-supported nickel disulfide nanoparticles promise stable and fast potassium storage.

Nickel sulfide (NiS2) is generally regarded as an appropriate anode for manufacturing new-type potassium-ion batteries (PIBs), while the development and application of NiS2 are hampered by poor intrinsic electrical conductivity and huge volumetric change during potassiation/de-potassiation. Herein, we construct self-adaptive NiS2 nanoparticles confined to a three-dimensional graphene oxide (NiS2/3DGO) electrode via in situ sulfurization and self-assembly processes. The as-obtained NiS2/3DGO exhibits high reversible capacity (391 mA h g-1) and outstanding rate behavior (stable cycling at 1000 mA g-1) for PIBs. Furthermore, in situ X-ray diffractometry and ex situ Raman test results elucidate partially reversible transformation from the cubic NiS2 phase to the KxNiS2 intermediate, followed by generating a Ni0 and K2S4 product. This phenomenon is caused by the conversion reaction mechanism of NiS2 nanocrystals along with an amorphous phase transition during the initial cycle. Such understandings may shed new light on the application of metal sulfides and give directions to design novel electrodes with desirable structural stability and lifespan.

A porous nickel cyclotetraphosphate nanosheet as a new acid-stable electrocatalyst for efficient hydrogen evolution.

The stability of non-precious metal-based electrocatalysts for the acidic hydrogen evolution reaction (HER) is of great importance. Here, we have used nickel cyclotetraphosphate (Ni2P4O12) nanosheet arrays as a HER electrocatalyst for the first time. The Ni2P4O12 arrays were obtained through a facile low-temperature phosphorylation process and possess superior HER catalytic activities and stability in acid. The Ni2P4O12 delivers a small overpotential of 131.8 mV at -10 mA cm-2 and a low Tafel slope of 47.8 mV dec-1 in 0.5 M H2SO4, comparable to most of the non-precious metal-based catalysts. Importantly, the Ni2P4O12 shows a negligible potential change (6.5 mV) over 80 000 s continuous testing in acid. The remarkable catalytic performances of Ni2P4O12 are mainly attributed to the inductive effect of P4O124- and its polymer-like structure, promoting it as a potential acid-stable HER electrocatalyst.