Photocatalysts derived from semiconductor heterojunctions that harvest solar energy and catalyze reactions still suffer from low solar‐to‐hydrogen conversion efficiency. Now, MXene (Ti3C2TX) nanosheets (MNs) are used to support the in situ growth of ultrathin ZnIn2S4 nanosheets (UZNs), producing sandwich‐like hierarchical heterostructures (UZNs‐MNs‐UZNs) for efficient photocatalytic H2 evolution. Opportune lateral epitaxy of UZNs on the surface of MNs improves specific surface area, pore diameter, and hydrophilicity of the resulting materials, all of which could be beneficial to the photocatalytic activity. Owing to the Schottky junction and ultrathin 2D structures of UZNs and MNs, the heterostructures could effectively suppress photoexcited electron–hole recombination and boost photoexcited charge transfer and separation. The heterostructure photocatalyst exhibits improved photocatalytic H2 evolution performance (6.6 times higher than pristine ZnIn2S4) and excellent stability.

Heteroatom doping is one of the most effective routes to adjust the physicochemical and optical properties of carbon dots (CDs). However, fluorine (F) doped CDs have been barely achieved. In this work, a F-doping strategy was proposed and adopted to modulate optical properties of CDs. A kind of F-doped CDs was synthesized by a solvothermal process using aromatic F bearing moiety as the F source and shows much longer maximum emissions (up to 600 nm, red fluorescence) than that of undoped CDs, indicating a large emission red-shift effect by F-doping. In addition, the F-doped CDs have remarkable water-solubility, high biocompatibility, as well as excellent stability even under broad pH range, ionic strengths, and light illumination and thus can be used as a novel probe for the highly efficient cell imaging of various normal cells and cancer cells. The F-doped CDs can selectively bind to Ag + . It therefore makes the F-doped CDs be a highly sensitive probe for the detection of Ag + under both aqueous solution and various biological systems. The huge potential of this F-doping strategy is indicated in the rational design of high-performance CDs, as well as in applications of clinical diagnosis and ion detection.

Stimuli-responsive polymeric hydrogels are promising and appealing delivery vehicles for protein/peptide drugs and have made protein/peptide delivery with both dosage- and spatiotemporal-controlled manners possible. Here a series of new Salecan-based pH-sensitive hydrogels were fabricated for controlled insulin delivery via the graft copolymerization reaction between Salecan and 2-acrylamido-2-methyl-1-propanesulfonic acid. In this study, on one hand, Salecan played a key role in modifying the structure and the pore size of the developing hydrogel. On the other hand, Salecan tuned the water content and the water release rate of the obtained hydrogel, leading to a controllable release rate of the insulin. More importantly, in vitro release experiments validated that the release of insulin from this intelligent system could be also tailored by the environmental pH of the release medium. For SGA2, the amount of encapsulated insulin released at gastric conditions (pH 1.2) was relatively low (about 26.1 wt % in 24 h), while that released at intestinal conditions (pH 7.4) increased significantly (over 50 wt % in 6 h). Furthermore, toxicity assays demonstrated that the designed hydrogel carriers were biocompatible. These characteristics make the Salecan-based hydrogel a promising candidate for protein/peptide drug delivery device.

Carbon dots (CDs) focus great attention in a broad range of adhibitions because of their excellent optical properties and high biocompatibility and property adjustability. However, the developed CDs have rarely been used as effective gene vectors until now. In this work, we devised and synthesized novel fluorine-doped cationic CDs (FCDs) using tetrafluoroterephthalic acid as a fluorine source and using branched polyethylenimine to furnish positive charge sites. The FCDs achieve dramatic positive EGFP and luciferase gene transfection efficiency as well as low cytotoxicity in commonly used cell lines at a low weight ratio, even in primary and stem cells. It is worth pointing out that the FCDs possess superior efficiency and biocompatibility, compared to some widely used commercial reagents such as 25 kDa polyethylenimine and Lipofectamine 2000. In addition, the FCDs show excellent efficient transfection even at high serum concentration and low DNA dose, indicating potential practical applications.

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Photocatalysts derived from semiconductor heterojunctions that harvest solar energy and catalyze reactions still suffer from low solar‐to‐hydrogen conversion efficiency. Now, MXene (Ti3C2TX) nanosheets (MNs) are used to support the in situ growth of ultrathin ZnIn2S4 nanosheets (UZNs), producing sandwich‐like hierarchical heterostructures (UZNs‐MNs‐UZNs) for efficient photocatalytic H2 evolution. Opportune lateral epitaxy of UZNs on the surface of MNs improves specific surface area, pore diameter, and hydrophilicity of the resulting materials, all of which could be beneficial to the photocatalytic activity. Owing to the Schottky junction and ultrathin 2D structures of UZNs and MNs, the heterostructures could effectively suppress photoexcited electron–hole recombination and boost photoexcited charge transfer and separation. The heterostructure photocatalyst exhibits improved photocatalytic H2 evolution performance (6.6 times higher than pristine ZnIn2S4) and excellent stability.