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981.
WANG Wei YUAN XiaQing LIU XuHui GAO Qiang QI HongLan ZHANG ChengXiao 《中国科学:化学(英文版)》2013,56(7):1009-1016
A selective DNA sensing with zeptomole detection level is developed based on coulometric measurement of gold nanoparticle (AuNPs)-mediated electron transfer (ET) across a self-assembled monolayer on the gold electrode. After immobilization of a thiolated hairpin-structured DNA probe, an alkanethiol monolayer was self-assembled on the resultant electrode to block [Fe(CN)6 ]-3-/4in a solution from accessing the electrode. In the presence of DNA target, hybridization between the DNA probe and the DNA target breaks the stem duplex of DNA probe. Consequently, stem moiety at the 3′-end of the DNA probes was removed from the electrode surface and made available for hybridization with the reporter DNA-AuNPs conjugates (reporter DNA-AuNPs). The thiolated reporter DNA matches the stem moiety at the 3′-end of the DNA probe. AuNPs were then enlarged by immersing the electrode in a growth solution containing HAuCl 4 and H2O2 after the reporter DNA-AuNPs bound onto the electrode surface. The enlarged AuNPs on the electrode restored the ET between the electrode and the [Fe(CN)6]3 -/4- , as a result, amplified signals were achieved for DNA target detection using the coulometric measurement of Fe(CN)6 3- electro-reduction by prolonging the electrolysis time. The quantities of ET on the DNA sensor increased with the increase in DNA target concentration through a linear range of 3.0 fM to 1.0 pM when electrolysis time was set to 300 s, and the detection limit was 1.0 fM. Correspondingly, thousands of DNA (zeptomole) copies were detected in 10L samples. Furthermore, the DNA sensor showed excellent differentiation ability for single-base mismatch. 相似文献
982.
FAN LeQing CHEN Yuan WU JiHuai LI ZhaoLei XIAO YaoMing HUANG MiaoLiang YU HaiJun 《中国科学:化学(英文版)》2013,56(10):1470-1477
Mesoporous TiO2microsphere(MTM)was synthesized via a simple solution route and then mixed with commercial TiO2(P25)to form highly homogeneous and stable TiO2colloid by simple hydrothermal treatment.The TiO2colloid was coated onto the plastic conductive substrate to prepare mesoporous TiO2film for flexible dye-sensitized solar cells(DSSCs)by low-temperature heat treatment.The influence of MTM content on the physicochemical properties of the flexible TiO2film was characterized by scanning electron microscope,transmission electron microscopy,X-ray diffraction,energy-dispersive X-ray spectrometer,N2adsorption-desorption isotherms,UV–vis absorption and diffuse reflectance spectra.It is revealed that with increasing the MTM content,the dye-loading capability of TiO2film and light-harvesting efficiency of flexible DSSCs are improved due to MTM having high surface area and acting as a light scattering center,respectively,resulting in the enhancement of photocurrent of flexible DSSCs.However,more and larger cracks having negative effect on the performances of flexible DSSCs are formed simultaneously.Under the optimal condition with MTM content of 20%,a flexible DSSC with overall light-to-electric energy conversion efficiency of 2.74%is achieved under a simulated solar light irradiation of 100 mW cm 2(AM 1.5),with 26%improvement in comparison with DSSCs based on P25 alone. 相似文献
983.
984.
Yi‐Chin Chen Sheng‐Cih Huang Dr. Yu‐Kuo Wang Dr. Yuan‐Ting Liu Prof. Dr. Tung‐Kung Wu Prof. Dr. Teng‐Ming Chen 《化学:亚洲杂志》2013,8(11):2652-2659
In this study, surface‐functionalized, branched polyethylenimine (BPEI)‐modified YVO4:Bi3+,Eu3+ nanocrystals (NCs) were successfully synthesized by a simple, rapid, solvent‐free hydrothermal method. The BPEI‐coated YVO4:Bi3+,Eu3+ NCs with high crystallinity show broad‐band excitation in the λ=250 to 400 nm near‐ultraviolet (NUV) region and exhibit a sharp‐line emission band centered at λ=619 nm under excitation at λ=350 nm. The surface amino groups contributed by the capping agent, BPEI, not only improve the dispersibility and water/buffer stability of the BPEI‐coated YVO4:Bi3+,Eu3+ NCs, but also provide a capability for specifically targeted biomolecule conjugation. Folic acid (FA) and epidermal growth factor (EGF) were further attached to the BPEI‐coated YVO4:Bi3+,Eu3+ NCs and exhibited effective positioning of fluorescent NCs toward the targeted folate receptor overexpressed in HeLa cells or EGFR overexpressed in A431 cells with low cytotoxicity. These results demonstrate that the ligand‐functionalized, BPEI‐coated YVO4:Bi3+, Eu3+ NCs show great potential as a new‐generation biological luminescent bioprobe for bioimaging applications. Moreover, the unique luminescence properties of BPEI‐coated YVO4:Bi3+,Eu3+ NCs show potential to combine with a UVA photosensitizing drug to produce both detective and therapeutic effects for human skin cancer therapy. 相似文献
985.
Yanjun Wang Shaoyun Chen Heng Chen Xingzhou Yuan Yongchun Zhang 《Journal of Energy Chemistry》2013,22(6):902-906
Removal of carbonyl sulfide (COS) from CO2 stream is significant for the production and utilization of food grade CO2. This study investigates the adsorption performance of Ag/NaZSM-5 as adsorbent prepared by incipient wetness impregnation for the removal of COS from a CO2 stream in a fixed-bed adsorption apparatus. Effects of various conditions on the preparation of adsorbent, adsorption and desorption were intensively examined. The results revealed that COS can be removed to below 1×10?9 from a CO2 stream (1000 ppm COS/CO2) using Ag/NaZSM-5 (10 wt% AgNO3) with an adsorption capacity of 12.86 mg-g?1. The adsorbent can be fully regenerated using hot air at 450 °C. The adsorption ability remained stable even after eight cycles of regeneration. 相似文献
986.
A novel strategy for selective collection and detection of breast cancer cells (MCF-7) based on aptamer–cell interaction was developed. Mucin 1 protein (MUC1) aptamer (Apt1) was covalently conjugated to magnetic beads to capture MCF-7 cell through affinity interaction between Apt1 and MUC1 protein that overexpressed on the surface of MCF-7 cells. Meanwhile, a nano-bio-probe was constructed by coupling of nucleolin aptamer AS1411 (Apt2) to CdTe quantum dots (QDs) which were homogeneously coated on the surfaces of monodispersed silica nanoparticles (SiO2 NPs). The nano-bio-probe displayed similar optical and electrochemical performances to free CdTe QDs, and remained high affinity to nucleolin overexpressed cells through the interaction between AS1411 and nucleolin protein. Photoluminescence (PL) and square-wave voltammetric (SWV) assays were used to quantitatively detect MCF-7 cells. Improved selectivity was obtained by using these two aptamers together as recognition elements simultaneously, compared to using any single aptamer. Based on the signal amplification of QDs coated silica nanoparticles (QDs/SiO2), the detection sensitivity was enhanced and a detection limit of 201 and 85 cells mL−1 by PL and SWV method were achieved, respectively. The proposed strategy could be extended to detect other cells, and showed potential applications in cell imaging and drug delivery. 相似文献
987.
Copper nanoclusters (Cu NCs) are found to possess intrinsic peroxidase-like activity for the first time. Similar to nature peroxidase, they can catalyze the oxidation of 3,3′,5,5′-tetramethylbenzidine by H2O2 to produce a nice blue color reaction. Compared with horseradish peroxidase, Cu NCs exhibits higher activity near neutral pH, which is beneficial for biological applications. The increase in absorbance caused by the Cu NCs catalytic reaction allows the detection of H2O2 in the range of 10 μM to 1 mM with a detection limit of 10 μM. A colorimetric method for glucose detection was also developed by combining the Cu NCs catalytic reaction and the enzymatic oxidation of glucose with glucose oxidase. Taking into account the advantages of ultra-small size, good stability, and high biocompatibility in aqueous solutions, Cu NCs are expected to have potential applications in biotechnology and clinical diagnosis as enzymatic mimics. 相似文献
988.
Zhihong Yan Jinbin Yuan Genhua Zhu Ying Zou Chunyan Chen Shaolei Yang Shouzhuo Yao 《Analytica chimica acta》2013
This study reported for the first time the use of cholesterol-functionalized magnetic nanoparticles (Fe3O4@SiO2@Chol) for the determination of polycyclic aromatic hydrocarbons (PAHs) in traditional Chinese medicine samples (TCMs) by high performance liquid chromatography (HPLC) coupled with fluorescence detection. The method was efficient, environmentally friendly, and fast. The solvent consumption of the proposed column is only half of the conventional column but with higher efficiency. Influencing factors, including sorbent amount, desorption solvent, sample volume and extraction time, were investigated in detail. Under the optimum conditions, good linearity (R2 > 0.991) was obtained over the range of 5–400 ng g−1, with limits of detection (LOD) 0.75, 0.50, 1.0, 0.56, 0.60, 0.84 and 0.80 ng g−1 for anthracene, fluoranthene, pyrene, chrysene, benzo[a]anthracene, benzo(b)fluoranthene and benzo(k)fluoranthene, respectively. 相似文献
989.
990.
Liu‐Bin Wei Hong‐E Yuan Jin‐Man Chen Qing‐Qing Wang Hui Wang Wen‐Cai Ye Guang‐Xiong Zhou 《Helvetica chimica acta》2013,96(1):150-157
Five new cycloartane glycosides, nervisides D–H ( 1 – 5 ), were isolated from the AcOEt‐ and H2O‐soluble portions of the 90% EtOH extract of the aerial part of the plant Nervilia fordii. The structures of the isolated glycosides were elucidated by extensive spectroscopic analysis including HR‐ESI‐MS and NMR data. The isolated nervisides D–H were evaluated for the cytotoxic activity in vitro against human‐tumor cell lines (CNE, Hep‐2 and HepG2) with the MTT method. 相似文献