Controllable synthesis of ZnS/PMMA nanocomposite hybrids generated from functionalized ZnS quantum dots nanocrystals

We reported controllable synthesis of ZnS nanocrystal-polymer transparent hybrids by using polymethylmethacrylate (PMMA) as a polymer matrix. In a typical run, the appropriate amounts of zinc chloride (ZnCl₂) and sodium sulfide (Na₂S) in the presence of 2-mercaptoethanol (ME) as the organic ligand were well dispersed in H₂O/dimethylformamide solution without any aggregation. In addition, the Mn-doped ZnS nanocrystals (NCs) were synthesized with similar method. Then, ZnS-PMMA hybrids were obtained via free radical polymerization in situ by using ZnS NCs functionalized with methacryloxypropyltrimethoxysilane (MPS). FT-IR characterization indicates the formation of robust bonding between ZnS NCs and the organic ligand. The TEM images show that ZnS NCs are well dispersed in PMMA matrix, and particle size of as-prepared ZnS NCs is about 2.6 nm, in agreement with the computing results of Brus’s model and Debye–Scherrer formula. The photoluminescence measurements present that ZnS NCs, Mn-doped ZnS NCs, and ZnS/PMMA hybrid show good optical properties.     

Concave Pt-Cu-Fe ternary nanocubes:One-pot synthesis and their electrocatalytic activity of methanol and formic acid oxidation

Concave nanostructures may be developed to improve the specific mass activity of a catalyst for formic acid and methanol electro-oxidation. In this work, we report the elctrocatalytic oxidation of methanol and formic acid in acid medium over concave Pt-Cu-Fe ternary nanocubes (NCs), obtained by the galvanic exchange of Pt and Fe on Cu NCs. The concave Pt-Cu-Fe NCs exhibited improved electrooxidation performance contrasted to Pt-Cu NCs and purchased commercial Pt/C as demonstrated by their improved durability, lower onset potential, and more preferable anti-poisoning properties. These properties are believed to originate from the tailored concave structure of the catalyst and possible synergetic effects among the components of the Pt-Cu-Fe NCs.     

水相中荧光CdSe纳米晶的优化合成与表征

Ⅱ-Ⅵ族半导体纳米粒子（也称半导体量子点（semiconductor quantum dots）简称NCs）由于其独特的光学、光化学、电化学以及非线性光学性质已逐渐引起人们的广泛关注。而Ⅱ-Ⅵ族NCs最诱人的 潜在应用是作为荧光探针应用于生物体系,在生命科学研究中起到定性和定量标记分子和细胞的作用。     

Novel high-sensitive fluorescent detection of deoxyribonuclease I based on DNA-templated gold/silver nanoclusters

Herein, fluorescent DNA-templated gold/silver nanoclusters (DNA-Au/Ag NCs) are presented as a novel probe for sensitive detection of deoxyribonuclease I (DNase I). The procedure is based on quenching fluorescence of DNA-Au/Ag NCs by DNase I digestion of the DNA (5′-CCCTTAATCCCC-3′) template. This decrease in fluorescence intensity permitted sensitive detection of DNase I in a linear range of 0.013–60 μg mL⁻¹, with a detection limit of 3 ng mL⁻¹ at a signal-to-noise ratio of 3. Furthermore, the practicality of this probe for detection of DNase I in human serum and saliva samples was validated, demonstrating its advantages of simplicity, selectivity, sensitivity and low cost. Importantly, satisfactory agreement between results obtained by the fluorescent method described here and high performance liquid chromatography (HPLC) further confirmed the reliability and accuracy of this approach.     

GdF_3∶Ce~(3+),Dy~(3+)@GdF_3∶Eu~(3+)核壳结构荧光粉溶剂热法制备及其多色发光性能研究

采用溶剂热法合成了核壳结构纳米荧光粉GdF_3∶Ce~(3+),Dy~(3+)@GdF_3∶Eu~(3+)。XRD衍射图样显示所制备纳米晶为正交相;在Ce~(3+)的8S7/2→6IJ激发峰激发下,该核壳结构具有明显的多色发光性能,而在相应的非核壳结构中却由于Ce~(3+)共掺导致Eu~(3+)出现荧光猝灭现象。基于CIE坐标,可以看出该体系的核壳结构具有比非核壳结构优越的发光性能,这主要是因为Gd~(3+)起到媒介离子的作用。最后,讨论了壳厚度对发光的影响,结果发现当核壳的量比为1∶3时,荧光粉具有最大的发光强度。     

A label-free and sensitive fluorescent assay for one step detection of protein kinase activity and inhibition

In this paper, a label-free, highly sensitive and simple assay for one step detection of protein kinase (PKA) activity and inhibition that avoids the fluorescent dye process has been established. The detection was based on the fluorescence (FL) quenching of peptide-Ag nanoclusters (Ag NCs) caused by antibody modified Au nanoparticles (anti-Au NPs) via fluorescence resonance energy transfer (FRET). With PKA and adenosine 5′-triphosphate (ATP) introduced, the substrate peptide of Ag NCs could react with PKA via targeted phosphorylation, and followed by the linking interactions between peptide-Ag NCs and anti-Au NPs. According to the fluorescence quenching of Ag NCs, the activity of protein kinase can be facilely monitored in the range of 0.1–2000 mU/μL with high sensitivity. The detection limit for PKA is 0.039 mU/μL. We further explored the inhibitory effect of H-89 for protein kinase activity. The developed method was also applied to the investigation of drug-induced PKA activation in HeLa cells, which provides a promising means for screening of kinase-related drugs and the clinical diagnosis of disease.     

胶体量子点电致发光器件的研究进展

胶体量子点因其性质稳定、可溶液加工、发光颜色易于调节、色彩饱和度高等优点在固体照明、平板显示、红外通讯等领域引起人们高度关注.本文详细介绍了最近胶体量子点电致发光领域取得的重要进展,包括基于 II-VI 族(CdSe、CdTe、PbS、PbSe),III-V 族(InAs、InP),和 I-III-VI 族(CuInS、CuInSe)的量子点电致发光二极管.     

CdTe nanocrystals sensitized chemiluminescence and the analytical application

It was found that the mixing of CdTe semiconductor nanocrystals (NCs) with luminol in the presence of KMnO₄ can induce a great sensitized effect on chemiluminescence (CL) emission. When the concentration of luminol, KMnO₄ and NaOH were fixed at 1 μM, 1 μM and 0.05 M, respectively, the most excellent performance can be obtained for the CdTe NCs sensitized CL. By means of CL and photoluminescence spectra, we suppose the enhanced CL signals resulted from the accelerated luminol CL induced by the oxidized species of CdTe NCs. Based on the finding, using thioglycolic acid-capped CdTe NCs as label and immunoglobulin G (IgG) as a model analyte, a CL immunoassay protocol for IgG content detection was developed. The strong inhibition effect of phenol compounds on luminol-KMnO₄-CdTe NCs CL system was also observed. All these findings demonstrated the possibility of semiconductor nanocrystals induced chemiluminescence to be utilized for more practical applications.     

基于氧化型谷胱甘肽保护的荧光金纳米团簇的制备及其对Fe~(3+)的检测

利用氧化型谷胱甘肽作为还原剂和稳定剂,通过绿色合成法制备了具有良好生物相容性的金纳米团簇(GSSG-Au NCs),其平均粒径大小为2.9 nm。以其为荧光探针实现了对Fe~(3+)的高灵敏检测,且对干扰离子具有高度选择性,线性范围宽(0.1~30μmol/L),检出限为0.03μmol/L。该方法用于实际水样(自来水、湖水和河水)中Fe~(3+)的测定,结果满意。     

ZnSe and copper-doped ZnSe nanocrystals (NCs): Optical absorbance and precise determination of energy band gap beside their exact optical transition type and Urbach energy

The using of a reliable and accurate new method (called in literature as derivation of absorption spectrum fitting (DASF)) for evaluation of the optical band gap (E_g) and also the exact nature of charge carriers optical transitions, is investigated in ZnSe and ZnSe:Cu nanocrystals (NCs) synthesized by rapid microwave irradiation. This method can be performed by using the output of UV–Visible spectroscopy. The obtained E_g values are within the range of 2.985–3.261 eV, depending to the microwave irradiation time and Cu dopant percentage (decreasing trend with increasing of irradiation time and Cu content). The DASF-based obtained results for ZnSe and ZnSe:Cu nanoparticles, showed the more precise values of band gap, with the same trend of previously qualitative reported data on the same samples. Also, the direct gap nature of their optical transitions was justified. To perform the method, there is no any need to the concentration of solutions and merely one need the direct absorption or transmission spectra. In other word, DASF technique was employed on ZnSe NCs to confirm its validity and to avoid non-precise reports on optical band gap which can affect on the device optimizations based on these samples. Moreover, using the values of E_g, refractive index and dielectric constant of each sample were obtained at the absorption edge. Also, the width of the tailing states in the gap (Urbach energy: E_Tail) was estimated and were within the range of 0.049–0.122 eV, which their very small values in compare with E_g imply to the sharp valence and conduction band edges; it means the good crystallinity nature of the produced samples.