One-Pot Green Synthesis of Nitrogen-Doped Carbon Quantum Dots for Cell Nucleus Labeling and Copper(II) Detection.

The doping of nitrogen into carbon quantum dots is vitally important for improved fluorescence performance. However, the synthesis of nitrogen-doped carbon quantum dots (N-CQDs) is usually conducted under strong acid and high temperature, which results in environmental pollution and energy consumption. Herein, the N-CQDs were prepared by a mild one-pot hydrothermal process. The hydrothermal reaction temperature was adjusted to control the particle size, nitrogen/carbon atomic ratio, and quantum yield. The products were water soluble with a narrow particle size distribution and good dispersion stability over a wide pH range. The N-CQDs could penetrate into the HeLa cell nucleus without any further functionalization. Moreover, the fluorescence of N-CQDs could be selectively quenched by Cu2+ , which suggested applications for the detection of Cu2+ in human plasma.

Gas-Flow Tailoring Fabrication of Graphene-like Co-Nx-C Nanosheet Supported Sub-10 nm PtCo Nanoalloys as Synergistic Catalyst for Air-Cathode Microbial Fuel Cells.

In this work, we presented a novel, facile, and template-free strategy for fabricating graphene-like N-doped carbon as oxygen reduction catalyst in sustainable microbial fuel cells (MFCs) by using an ion-inducing and spontaneous gas-flow tailoring effect from a unique nitrogen-rich polymer gel precursor which has not been reported in materials science. Remarkably, by introduction of trace platinum- and cobalt- precursor in polymer gel, highly dispersed sub-10 nm PtCo nanoalloys can be in situ grown and anchored on graphene-like carbon. The as-prepared catalysts were investigated by a series of physical characterizations, electrochemical measurements, and microbial fuel cell tests. Interestingly, even with a low Pt content (5.13 wt %), the most active Co/N codoped carbon supported PtCo nanoalloys (Co-N-C/Pt) exhibited dramatically improved catalytic activity toward oxygen reduction reaction coupled with superior output power density (1008 ± 43 mW m-2) in MFCs, which was 29.40% higher than the state of the art Pt/C (20 wt %). Notability, the distinct catalytic activity of Co-N-C/Pt was attributed to the highly efficient synergistic catalytic effect of Co-Nx-C and PtCo nanoalloys. Therefore, Co-N-C/Pt should be a promising oxygen reduction catalyst for application in MFCs. Further, the novel strategy for graphene-like carbon also can be widely used in many other energy conversion and storage devices.

Thermal sensitivity and protein anti-adsorption of hydroxypropyl cellulose-g- poly(2-(methacryloyloxy) ethyl phosphorylcholine).

Zwitterionic graft copolymers, hydroxypropyl cellulose graft poly(2-(methacryloyloxy) ethyl phosphorylcholine) (HPC-g-PMPC) with well-defined architecture were synthesized by atom transfer radical polymerization (ATRP). The self-assembly behaviors and thermal sensitivity of HPC-g-PMPC copolymers and their correlations with graft density and side chain length were investigated in details. HPC-g-PMPC copolymers can self-assemble into spherical aggregate structure above the critical aggregation concentration (CAC) at room temperature. Meanwhile, the size of the aggregates mainly depended on the graft density. The obtained aggregates were thermal sensitive and their low critical solution temperature (LCST) was efficiently regulated by varying the graft density. Above the LCST, the aggregates were transferred into aggregates with core-shell structure, in which the HPC rich core was stabilized by the PMPC rich shell. The interaction between the HPC-g-PMPC aggregates and BSA was investigated. The results indicated that the anti-adsorption of BSA on the aggregates surface depended on the length and graft density of the PMPC zwitterionic side chains.