Facile template-based high-yield-transformation synthesis and electrocatalytic properties of PdTe nanowires

PdTe nanowires with well-defined morphology are prepared by a simple Te nanowire-template-based pathway. The as-prepared PdTe nanowires present a small diameter (about 12 nm) and long length (several tens of microns). After the electrochemical activation process, the prepared PdTe nanowire catalyst reveals a better catalytic ability for ethylene glycol electrooxidation in alkaline conditions when compared with a commercial Pd/C catalyst

Functionalized graphene/Fe3O4 supported AuPt alloy as a magnetic, stable and recyclable catalyst for a catalytic reduction reaction

Herein, branched poly-(ethylenimine) functionalized graphene/iron oxide hybrid (termed as BGNs/Fe3O4) was chosen as an efficient support material to load AuPt alloy nanoparticles for constructing a multifunctional nanocatalyst via a simple and controlled self-assembly approach. BGNs/Fe3O4 as a nanocarrier made the AuPt alloy nanoparticles uniformly distributed on the surface of BGNs/Fe3O4. The obtained multifunctional nanocatalyst was characterized by high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray (EDX) spectroscopy, UV-Vis spectroscopy and X-ray photoelectron spectroscopy (XPS). The nanocatalyst exhibited favorable water solubility, excellent dispersion, good stability, superparamagnetism and particularly high catalytic activity for reducing 4-nitrophenol (4-NP). Furthermore, by tuning the composition of the nanoalloy nanoparticles of the multifunctional nanocatalyst, a normalized rate constant of about 17.99 mg(-1) s(-1) was achieved, which was superior to most of the Au or Pt based nanocatalysts reported in recent years. In addition, it was proved that the magnetic Fe3O4 nanoparticles not only ensured the reuse of the nanocatalyst, but also significantly improved the catalytic activity. Thanks to the favorable catalytic activity, the obtained multifunctional nanocatalyst may hold great potential for various catalytic processes

Nanofibrous microspheres via emulsion gelation and carbonization

Nanofibrous hydrogel microspheres are formed by pH gelation of perylene diimide derivatives in emulsion droplets. These microspheres are freeze-dried and subsequently carbonized to produce discrete N-doped nanofibrous carbon microspheres. The carbon microspheres show high performance as electrode materials for supercapacitors

Base-Promoted Consecutive Enolate Addition Reaction of [60]Fullerene with Ketones

[60]Fullerene derivatives with novel 1,4,9,25- and 1,4,9,12-configurations were obtained by reactions of C-60 with aliphatic ketones and benzyl bromide under basic conditions. The structures of the products were determined by X-ray single-crystal diffraction and spectroscopic characterization. The reactions were rationalized by a monoenolate addition experiment and in situ vis-NIR spectroscopy

Engineering Hybrid Metallic Nanostructures Using a Single Domain of Block Copolymer Templates

Building complex nanostructures using a simple patterned template is challenging in material science and nanotechnology. In the present work, three different strategies have been exploited for the successful fabrication of hybrid dots-on-wire metallic nanostructures through combining an in-situ method with an ex-situ method. Basically, plasma etching was applied to generate a metallic wire-like nanostructure, and preformed nanoparticles could be placed through multiple means before or after the formation of the wire-like nanostructure. Various monometallic and bimetallic nanostructures have been obtained by utilizing only one functional domain of block copolymer templates. In these cases, full utilization of the functional domain or introduction of the molecular linker is critical to engineering hybrid metallic nanostructures. Other complex and multifunctional hybrid nanostructures can be developed via these strategies similarly, and these nanostructures are promising for useful applications such as optics and surface-enhanced Raman spectroscopy (SERS)

Guanidinated Thiourea-Decorated Polyethylenimines for Enhanced Membrane Penetration and Efficient siRNA Delivery

RNA interference (RNAi) provides the promising treatments of gene-related diseases while hindered by the lack of highly efficient delivery platform with low cytotoxicity. Moreover, the intracellular fates of nonviral gene carriers are closely related to their internalization pathway, and eventually influence their RNAi efficiency. Herein, a series of guanidinated thiourea-modified polyethylenimines (PEI-MTU-Gs) are synthesized and utilized as the efficient carriers of small interfering RNA (siRNA) with up to 71.6% inhibition of luciferase activity in the luciferase-expressing cell lines (i.e., HeLa/Luc cells). The introduction of noncationic hydrogen bond donors, that is, thiourea groups, provides the carriers with much lower cytotoxicities and relatively looser complex structures that facilitate the intracellular release of siRNAs. Furthermore, the multiguanidino structures endow the PEI-MTU-G/siRNA complexes with the ability to directly penetrate cell membrane, which facilitates the cellular internalization while avoiding them suffering from the rigorous lysosomes. The results demonstrate PEI-MTU35-Gs as promising siRNA carriers for further gene therapy

Competitive binding-accelerated insulin release from a polypeptide nanogel for potential therapy of diabetes

A kind of glucose-sensitive polypeptide nanogel was prepared via a two-step procedure. First, methoxy poly(ethylene glycol)-block-poly(gamma-benzyl-L-glutamate-co-(gamma-propargyl-L-glutamate-graft-glucose) (mPEG-b-P(BLG-co-(PLG-g-Glu))) was synthesized by clicking 2'-azidoethyl-O-alpha-D-glucopyranoside to the PLG unit in mPEG-b-P(BLG-co-PLG), which was synthesized by the ring-opening polymerization (ROP) of gamma-benzyl-L-glutamate N-carboxyanhydride and gamma-propargyl-L-glutamate N-carboxyanhydride with mPEG-NH2 as the macroinitiator. The novel nanogel was subsequently prepared by cross-linking the glucose moieties through adipoylamidophenylboronic acid (AAPBA). The formation of the nanogel, i.e. the successful incorporation of phenylboronic acid (PBA) in the core, was systematically verified. The resultant nanogel showed a remarkable glucose-sensitivity in phosphate-buffered saline (PBS). Thus, insulin as a model drug was loaded into the glucose-sensitive polypeptide nanogel. The in vitro drug release profiles revealed that the release of insulin from the nanogel could be triggered by the presence of glucose through a competitive binding mechanism with the conjugated glucose. In detail, a faster release rate and a larger amount of released insulin were observed by the increased glucose concentration in PBS, which confirmed the potential application of the nanogel. Furthermore, the excellent cytocompatibility and hemocompatibility of the nanogel were demonstrated. Therefore, the biocompatible nanogel with an intelligent capacity for glucose-accelerated payload release should be promising for applications in diabetes treatment

聚合物诱导苝探针自组装在生物分析中的应用

荧光分析方法，因其灵敏度高，操作简单，已经受到了人们广泛关注，在生物、环保、医药、石油勘探等诸多领域都有广泛的应用。这些年，人们发展了许多基于先进功能材料如共轭聚电解质，量子点，金纳米粒子，纳米簇，碳纳米点等等的荧光传感战略。相比于这些材料，小分子探针具有相对简单的化学结构，易于合成和修饰等优点。本论文中，我们着重研究了聚合物（聚电解质）诱导的苝衍生物探针分子的可控自组装性质，并且将此性质应用于生物分析检测，发展了简单灵敏，免标记的荧光检测新方法。其主要内容如下： 第一部分工作：基于聚电解质诱导的苝衍生物探针的非共价自组装，以及λ核酸外切酶的特异性切割作用，我们发展了一种检测碱性磷酸酶活性的新方法。首先，我们合成了一种带有负电荷的苝酰亚胺衍生物分子作为荧光探针，带有正电荷的聚电解质能够通过非共价静电相互作用力诱导探针分子集聚，探针的单体荧光被有效的猝灭，此时，如果向溶液中加入带负电荷的单链...Fluorescent methods have received considerable attention during the past several decades owing to its easy operation and high detection sensitivity. They have been widely used for biological technology, environmental protection, medicine, and oil exploration. In recent years, many fluorescent sensors have been developed, such as conjugated polyelectrolytes, quantum dots, gold nanoclasters and carbon nanodots based methods. Compared with these advanced fluorescent materials, small molecular probes have relatively simple chemical structure, which can be synthesized and functionalized more easily. Perylene derivatives have been used as excellence fluorescent probes. In this work, we foucs on polyeletrolyte-induced perylene probe controlled self-assembly and its applications for bioanlysis. Th..

Preparation of biocompatible, biodegradable and sustainable polylactides catalyzed by aluminum complexes bearing unsymmetrical dinaphthalene-imine derivatives via ring-opening polymerization of lactides

A number of half-salen aluminum complexes bearing unsymmetrical [ONN]-type ligands were prepared from tridentate dinaphthalene-imine derivatives. These complexes were characterized by H-1 and C-13 NMR spectroscopy, elemental analysis and single crystal X-ray diffraction analysis. These complexes were employed for rac-lactide and L-lactide polymerization. Upon activation with isopropanol, complex (S)-B-6 (R-1 = R-2 = R-4 = H; R-3 = F) showed the highest activity (a monomer conversion of 94.6%) amid these aluminum complexes for the ring-opening polymerization of L-lactide; and complex (S)-B-2 (R-1 = R-2 = R-3 = H; R-4 = Bu-t) showed the highest stereoselectivity for the ring-opening polymerization of rac-lactide, obtaining a polylactide (PLA) with a Pm of 0.69. The polymerization kinetics utilizing (S)-B-6 as a catalyst were researched in detail. The data on the polymerization kinetics revealed that the rate of polymerization was first-order with respect to the monomer and the catalyst. There was a linear relationship between the L-lactide conversion and the number-average molecular weight of PLA

Synthesis and Application of Nanohybrids Based on Upconverting Nanoparticles and Polymers

Lanthanide-doped upconversion nanoparticles (UCNPs) have been an emerging and exciting research field in recent years due to their unique luminescent properties of converting near-infrared light to shorter wavelength radiation. UCNPs offer excellent prospects in luminescent labeling, displays, bioimaging, bioassays, drug delivery, sensors, and anticounterfeiting applications. Along with the abundant studies and rapid progress in this area, UCNPs are promising to be a new class of luminescent probe owing to their special advantages over the conventional organic dyes and quantum dots. Among them, polymers play an important role to improve properties or endow new function of UCNPs such as for matrix materials, water solubility, linking active targeting molecules, biocompatibility, and stimuli-responsive behavior. This article briefly reviews the compositions, optical mechanisms, architectures of upconversion nanocrystals and highlights the works on various functional UCNPs/polymer nanohybrids as well as many new interesting fruits in applications