A New Dual-peak Fluorescent Probe for Water Content Detection Made From Taxus

In this paper, the leaves of Taxus were used as the sole carbon source, and two kinds of carbon dots blue and red, with different properties, were synthesized by the hydrothermal method under different conditions. The red carbon dots were quenched in the water, and the blue carbon dots had stable fluorescence properties in water environment. The bimodal fluorescence probe formed by mixing could accurately and stably measure the water content in ethanol, which was in the range of 82.5%-100%, is highly correlated with the fluorescence intensity ratio (I₄₈₁/I₆₇₈) of mixed carbon dots under 390 nm excitation light, with R²?=?0.995 and the detection limit as low as 0.31%. The experimental materials are environmentally friendly, low in cost, and simple to operate, as well as the water content measured by proportional fluorescence has high accuracy, which provides a new method for measuring moisture in ethanol.

     

Miniaturization of Metal–Biomolecule Frameworks Based on Stereoselective Self‐Assembly and Potential Application in Water Treatment and as Antibacterial Agents

Miniaturization of metal–biomolecule frameworks (MBioFs) to the nanometer scale represents a novel strategy for fabricating materials with tunable physical and chemical properties. Herein, we demonstrate a simple, low‐cost, and completely organic solvent‐free strategy for constructing a dl ‐glutamic acid–copper ion‐based three‐dimensional nanofibrous network structure. The building blocks used are available in large quantities and do not require any laborious synthesis or modification. Importantly, we demonstrate with an intriguing example, that the self‐assembly ability of supramolecular nanofibers could be finely tuned with the ligands’ chirality. This offers opportunities for obtaining one‐dimensional hierarchical nanostructures and expands the investigation scope of stereoselective self‐assembly. Furthermore, the material displays good ability in removing anionic dyes from water and inhibits the growth of both Gram positive and Gram negative bacteria, possibly through the contact‐killing mechanism; this indicates potential applications in environmental issues and antimicrobial nanotherapeutics.     

A new isobenzofuranone derivative from a marine Streptomyces sp.

One new isobenzofuranone derivative,1,4-dimethoxy-3-(3R*-hydroxy-3R*-methyl-1-tetralone)-1(3H)-isobenzofuran(1),was isolated from the broth of marine Streptomyces sp.M268.The structure was elucidated by spectroscopy characteristics as well as comparison with the literature.Compound 1 exhibited cytotoxicities against human cancer cell,HL-60,A549,and BEL-7402.     

Fluorescent detection of silver(I) and cysteine using SYBR Green I and a silver(I)-specific oligonucleotide

We report on a novel method for the determination of silver ion (Ag⁺) and cysteine (Cys) by using the probe SYBR Green I (SGI) and an Ag+-specific cytosine-rich oligonucleotide (C-DNA). The fluorescence of SGI is very weak in the absence or presence of randomly coiled C-DNA. If, however, C-DNA interacts with Ag⁺ through the formation of cytosine-Ag⁺-cytosine (C-Ag⁺-C) base pairs, the randomly coiled C-DNA undergoes a structural changes to form a hairpin-like structure, thereby increasing the fluorescence of SGI. This fluorescence turn-on process allows the detection of Ag⁺ in the 10–600?nM concentration range, with a detection limit of 4.3?nM. Upon the reaction of Ag⁺ with Cys, Cys specifically removes Ag⁺ from the C-Ag⁺-C base pairs and destroys the hairpin-like structure. This, in turn, results in a decrease in fluorescence intensity. This fluorescence turn-off process enables the determination of Cys in the 8–550?nM concentration range, with a detection limit of 4.5?nM. The method reported here for the determination of either Ag⁺ or Cys is simple, sensitive, and affordable, and may be applied to other detection systems if appropriately selected DNA sequences are available.

A simple and efficient fluorescent sensor for histidine

A simple coordination complex terpyridine-CuCl(2) is found to be an efficient fluorescent sensor for histidine in aqueous solution with up to 1004 fold fluorescence enhancement.     

Graphene anchored with mesoporous NiO nanoplates as anode material for lithium-ion batteries

Graphene is an excellent substrate to load nanomaterials for energy applications due to its large surface area, excellent conductivity, mechanical strength, and chemical stability. In this study, thermal exfoliated functionalized graphene sheets with good conductivity and high BET surface area are anchored with mesoporous NiO nanoplates by in situ chemical synthesis approach. Electrochemical characterization shows that functionalized graphene sheets–NiO sample exhibits a high capacity of about 700 mAh/g at a discharge current density of 100 mA/g and a good cycling ability. The high capacity and good cycling ability of functionalized graphene sheets –NiO material were attributed to the intimate interaction between the graphene sheets and NiO nanoplates. The graphene sheets not only enhance the conductivity of NiO nanoplates but also improve the structure stability of NiO nanoplates. Furthermore, the mesoporous structure of NiO nanoplates is available to the transfer of electrolyte. Such functionalized graphene sheets–NiO nanocomposite could be a promising candidate material for a high-capacity, low cost, and nontoxic anode for lithium-ion batteries.     

Synthesis and properties of naphthobisbenzo[b]thiophenes: structural curvature of higher acene frameworks for solubility enhancement and high-order orientation in crystalline states

The syntheses of naphtho[2,3-b:7,6-b′]- and naphtho[2,1-b:5,6-b′]bisbenzo[b]thiophenes (NBBTs) are achieved via inter- and intramolecular stepwise Friedel–Crafts-type reactions. The structural curvature of these NBBTs are found to improve their solubility in organic solvents, and to form well-defined herringbone structures in single crystals, especially when the C_2v symmetrical naphtho[2,3-b:7,6-b′]bisbenzo[b]thiophene takes the form of asymmetric space groups in a parallel direction with each other, and having exhibited OFET characteristics with a hole mobility of 7 × 10^?5 cm² V^?1 s^?1.     

壳聚糖-树枝状大分子杂化物的研究进展

壳聚糖-树枝状大分子杂化物主要包括壳聚糖-(聚酰胺-胺)[CS-PAMAM]、壳聚糖-聚乙烯亚胺[CS-PEI]、壳聚糖-3,4,5-三(p-十二烷氧基苄氧基)苯甲酸[CS-DOBOB酸]、壳聚糖-3,4,5-三(p-十二烷氧基-m-甲氧基苄氧基)苯甲酸(DOVOB酸)、壳聚糖-聚丙三醇(PGLD)等树枝状大分子杂化物。壳聚糖-树枝状大分子杂化物具有良好的水溶性、生物可降解性、抗菌性、吸附性和热致液晶性等性能。壳聚糖-树枝状大分子杂化物的用途广泛,可作为金属离子的吸附剂、治疗高胆红素血症的吸附材料、新型荧光材料、抗菌剂和抗凝血剂等。本文综述了壳聚糖-树枝状大分子杂化物的研究进展,并展望了其未来研究方向和应用前景。     

Glycosylated star-shaped conjugated oligomers for targeted two-photon fluorescence imaging

A glucopyranose functionalized star-shaped oligomer, N-tris{4,4',4'-[(1E)-2-(2-{(E)-2-[4-(benzo[d]thiazol-2-yl)phenyl]vinyl}-9,9-bis(6-2-amido-2-deoxy-1-thio-β-D-glucopyranose-hexyl)-9H-fluoren-7-yl)vinyl]phenyl}phenylamine (TVFVBN-S-NH(2)), is synthesized for two-photon fluorescence imaging. In water, TVFVBN-S-NH(2) self-assembles into nanoparticles with an average diameter of ～49?nm and shows a fluorescence quantum yield of 0.21. Two-photon fluorescence measurements reveal that TVFVBN-S-NH(2) has a two-photon absorption cross-section of ～1100 GM at 780?nm in water. The active amine group on the glucopyranose moiety allows further functionalization of TVFVBN-S-NH(2) with folic acid to yield TVFVBN-S-NH(2) FA with similar optical and physical properties as those for TVFVBN-S-NH(2). Cellular imaging studies reveal that TVFVBN-S-NH(2) FA has increased uptake by MCF-7 cells relative to that for TVFVBN-S-NH(2), due to specific interactions between folic acid and folate receptors on the MCF-7 cell membrane. This study demonstrates the effectiveness of glycosylation as a molecular engineering strategy to yield water-soluble materials with a large two-photon absorption (TPA) cross-section for targeted cancer-cell imaging.