In-Situ Template Formation Strategy for the Preparation of Nitrogen Doped Carbon Nanocage with Graphitic Shell as Electrode Material for Supercapacitor.

Nitrogen doped carbon nanocage with graphitic shell (NGCS) was fabricated through in-situ solid reaction between calcium acetate and dicyandiamide in an inert atmosphere followed by acid etching. The role played by the calcium acetate (Ca(Ac)2) and dicyandiamide (DCD) during the synthesis process is one-stone-two-birds. Calcium acetate plays multiple functions: template agent, graphitization catalyst, and carbon source. Dicyandiamide can be considered as the nitrogen sources and the chemical reaction agent that can be reacted with calcium acetate to form it into CaCN2. The NGCS obtained at 800 °C has a specific surface area of 420 m2/g and nitrogen content of 8.87 at%. The excellent electrochemical performance can be attributed to the combination effects of porous structure, nitrogen doping and graphitized nanocage shell of NGCS electrode. The hollow structure serves as the reservoir for fast electrolyte ion supplement. Nitrogen groups not only improve the wettability of interfaces between carbon surface and electrolyte, but also generate extra pseudocapacitance through redox reaction. The graphitic carbon nanocage shell can enhance the conductivity and facilitates the fast charge transfer. At a current density of 0.5 A/g, the specific capacitance of the NGCS-800 electrode is 215 F/g. Furthermore, the NGCS-800 electrode exhibits excellent rate capability (80% capacitance retention at 10 A/g) and outstanding cycling stability (96.89% capacitance retention after 5000 cycles). These intriguing results demonstrate that nitrogen doped carbon with graphitic shell will be highly promising as electrode materials for supercapacitors and other energy storage and conversation applications.

A multifunctional targeting probe with dual-mode imaging and photothermal therapy used in vivo.

BACKGROUND: Ag2S has the characteristics of conventional quantum dot such as broad excitation spectrum, narrow emission spectrum, long fluorescence lifetime, strong anti-bleaching ability, and other optical properties. Moreover, since its fluorescence emission is located in the NIR-II region, has stronger penetrating ability for tissue. Ag2S quantum dot has strong absorption during the visible and NIR regions, it has good photothermal and photoacoustic response under certain wavelength excitation. RESULTS: 200 nm aqueous probe Ag2S@DSPE-PEG2000-FA (Ag2S@DP-FA) with good dispersibility and stability was prepared by coating hydrophobic Ag2S with the mixture of folic acid (FA) modified DSPE-PEG2000 (DP) and other polymers, it was found the probe had good fluorescent, photoacoustic and photothermal responses, and a low cell cytotoxicity at 50 µg/mL Ag concentration. Blood biochemical analysis, liver enzyme and tissue histopathological test showed that no significant influence was observed on blood and organs within 15 days after injection of the probe. In vivo and in vitro fluorescence and photoacoustic imaging of the probe further demonstrated that the Ag2S@DP-FA probe had good active targeting ability for tumor. In vivo and in vitro photothermal therapy experiments confirmed that the probe also had good ability of killing tumor by photothermal. CONCLUSIONS: Ag2S@DP-FA was a safe, integrated diagnosis and treatment probe with multi-mode imaging, photothermal therapy and active targeting ability, which had a great application prospect in the early diagnosis and treatment of tumor.

Synthesis, protein-binding ability and phytoalexin-elicitor activity of epoxyalkyl (1-->3)-beta-D-oligoglucosides.

We describe a approach for the synthesis of (1-->3)-beta-D-oligosaccharide derivatives 10-18. 1-9 were synthesized by treating peracetylated (1-->3)-beta-D-oligosaccharides with the corresponding alkenyl alcohols and Lewis acid (SnCl(4)) catalyst. Epoxidation of the corresponding alkenyl oligoglucosides took place by m-CPBA. NaOMe in dry methanol was used for the deacetylation of the blocked derivatives, to give 10-18 in an overall yields of 25-32%. In subsequent glucan-binding protein of soybean assays, we found that 16 was most active, with an IC(50) value of 9 mM. However, the activities of 17, 18, 13, 14, 15, 10, 11, and 12 were gradually decreased. At the same time, we found 16 was most active as compared to the other (1-->3)-beta-D- oligoglucoside derivatives in eliciting phytoalexin accumulation in soybean cotyledon tissue, and 16 was kept longer time than (1-->3)-beta-D-glucohexaose, which indicated 16 is much more stable than (1-->3)-beta-D-glucohexaose.