Dramatic red fluorescence enhancement and emission red shift of carbon dots following Zn/ZnO decoration

Dramatic red fluorescence enhancement and emission red shift of carbon dots following Zn/ZnO decoratio

Efficient Noble‐Metal‐Free Catalysts Supported by Three‐Dimensional Ordered Hierarchical Porous Carbon

Development of heterogeneous catalysts has attracted increasing attention, owing to their remarkable catalytic performance and recyclability. Herein, we report well-developed heterogeneous catalysts with a three-dimensional ordered hierarchical structure, constructed from nickel or cobalt nanoparticles embedded in porous carbon. The obtained catalysts were fully characterized by several techniques. On account of the uniform distribution of metal nanoparticles in the porous carbon matrix and large diffusion channels that allow for effective mass transport, the catalysts exhibited superior catalytic performance for styrene epoxidation reaction. In particular, the catalysts showed good catalytic activity, high selectivity and excellent recyclability toward the styrene epoxidation. Thus, this facile approach developed allows for fabricating advanced heterogeneous catalysts with high catalytic activities for useful practical applications.National Research Foundation (NRF)This work is supported by the Singapore National Research Foundation Investigatorship (NRF-NRFI2018-03)

Large Emission Red-Shift of Carbon Dots by Fluorine Doping and Their Applications for Red Cell Imaging and Sensitive Intracellular Ag⁺ Detection

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

Fluorine-Doped Cationic Carbon Dots for Efficient Gene Delivery

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

Smart Macroporous Salecan/Poly(<i>N</i>,<i>N</i>‑diethylacrylamide) Semi-IPN Hydrogel for Anti-Inflammatory Drug Delivery

Poly­(<i>N</i>,<i>N</i>-diethylacrylamide) is not only a thermosensitive polymer, but also a good hydrogen bond acceptor. Therefore, drugs with carboxyl groups can serve as hydrogen bond donors and form interactions with the tertiary amide groups in <i>N</i>,<i>N</i>-diethylacrylamide. Herein, we report a novel drug delivery system for anionic drugs composed of poly­(<i>N</i>,<i>N</i>-diethylacrylamide) and salecan. Salecan was used to improve the hydrophilicity and accelerate the responsive rate of this system. As expected, salecan-enriched hydrogels exhibited higher swelling ratios and were more sensitive to temperature. Moreover, scanning electron microscopy images showed that the hydrogels are superporous structures, with pore-sizes that increase with salecan concentration. The swelling ratios decreased continuously with the increase of temperature in the range 25–37 °C. MTT assay for cell viability and cell adhesion studies confirm the cell compatibility of the system. Delivery tests using diclofenac sodium, an anti-inflammatory drug, indicate that the thermosensitive property of this system is favorable for anionic drug delivery. Interestingly, the release rates of diclofenac sodium from the hydrogels were temperature dependent, with higher temperatures contributing toward faster release rate