JOURNAL OF HAZARDOUS MATERIALS
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2015
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IF 4.529
Jian Rong Zhang,Ai Lian Zeng,Hong Qun Luo,Nian Bing Li
In this work, a simple and sensitive Cr(VI) sensor is proposed based on fluorescent polyethyleneimine-stabilized Ag nanoclusters, which allows the determination over a wide concentration range of 0.1 nM–3.0 μM and with a detection limit as low as 0.04 nΜ and a good selectivity. The quenching mechanism was discussed in terms of the absorption and fluorescence spectra, suggesting that Cr(VI) is connected to Ag nanoclusters by hydrogen bond between the oxygen atom at the vertex of tetrahedron structure of Cr(VI) and the amino nitrogen of polyethyleneimine that surrounded Ag nanoclusters and electron transfer from Ag nanoclusters to highly electron-deficient Cr(VI) results in fluorescence quenching. Despite the failure to quench the fluorescence efficiently, Cr(III) can also be measured using the proposed Ag nanoclusters by being oxidized to Cr(VI) in alkaline solution (pH ∼9) containing H 2 O 2 . Therefore, our approach could be used to detect Cr(VI), Cr(III) and the total chromium level in aqueous solution. In addition, Cr(VI) analysis in real water samples were satisfactory, indicating this method could be practically promising for chromium measurements.
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BIOSENSORS & BIOELECTRONICS
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2015
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IF 6.409
Pei Zou,Yaling Liu,Hongyong Wang,Jun Wu,Feifan Zhu,Hao Wu
Detection of ultralow concentration of specific protein plays a key role in biotechnological applications and medical diagnostics. In this study, we demonstrate an amplified chemiluminescence biosensing platform for sensitive detection of protein. The biosensing platform ingeniously combines target-catalyzed hairpin assembly and Exo III-assisted signal amplification . A catalytic G-quadruplex-hemin DNAzyme is further employed to stimulate the generation of chemiluminescence in the presence of luminol and H 2 O 2 . These designs together allow a high sensitivity for the biotarget, human α-thrombin, resulting in a detection limit of 0.92 pM, and it is much lower than previous reported studies. In addition, the proposed biosensing platform is versatile. By conjugating with various recognition units, it could be employed to sensitive detect various DNA-binding proteins and might find wide applications in biomedical fields .
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JOURNAL OF CHROMATOGRAPHY B-ANALYTICAL TECHNOLOGIES IN THE BIOMEDICAL AND LIFE SCIENCES
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2013
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IF 2.487
Guimei Zhu,Shihua Long,Hao Sun,Wen Luo,Xia Li,Zaibin Hao
A novel sensitive method based on tertiary amine labeling for the analysis of gibberellins (GAs) by capillary electrophoresis (CE) coupled with electrochemiluminescence (ECL) detection was proposed. GA 3 was tagged with 2-(2-aminoethyl)-1-methylpyrrolidine (AEMP) using N, N′-dicyclohexylcarbodiimide (DCC) and 3,4-dihydro-3-hydroxy-4-oxo-1,2,3-benzotriazine (HOOBt) as coupling agents in acetonitrile to produce GA 3 -AEMP-derivative. The GA 3 -AEMP-derivative was injected into CE by electrokinetic injection and detected by Ru(bpy) 3 2+ -based ECL . The parameters affecting derivatization, detection and separation such as concentration of reactants, detection potential, pH and concentration of separation buffer, were investigated in detail. Under optimum conditions, the linear concentration range for GA 3 was from 2.0 × 10 −7 to 1.28 × 10 −4 M with a correlation coefficient of 0.9997. The detection limit was 8 × 10 −8 M (S/N = 3). The relative standard deviations of migration time, peak intensity and peak area for nine continuous injections of 2.0 × 10 −5 M GA 3 -AEMP-derivative were 1.0%, 2.1% and 4.2%, respectively. The developed approach was successfully applied to the determination of total GAs in the stem, leaf and seed of soybean ( Glycine max [L.] Merr.) with recoveries in the range from 89.6% to 99.3%.
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ANALYST
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2013
·Vol. 139
·期 2
·488-494
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IF 3.969
Xinxin Xiao,Hui Li,Meng'en Wang,Kai Zhang,Pengchao Si
Nanoporous gold (NPG) based biosensors have been constructed by covalently immobilizing glucose oxidase (GOx) onto self-assembled monolayers (SAMs). With p-benzoquinone (BQ) as a mediator, diffusion behavior and amperometric biosensor performance are evaluated by electrochemical characterization. The enzyme modified electrodes are demonstrated to show a thickness-sensitive behavior. Compared with planar polycrystalline gold, the unique porous structure of NPG has also been characterized via an electrochemical surface reconstruction process. Single-crystal gold-like electrochemical behavior on NPG and a comprehensive understanding of its impacts on sensor performance have been proposed.
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JOURNAL OF ELECTROANALYTICAL CHEMISTRY
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2013
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IF 2.672
Bang Lin Li,Jing Rong Chen,Hong Qun Luo,Nian Bing Li
Silver nanoclusters (AgNCs) synthesized by using polyethyleneimine as a stabilizing scaffold have been confirmed as a novel material to exhibit high electrocatalytic activity for the reduction of hydrogen peroxide in this paper. The novel hydrogen peroxide electrochemical sensor was originally prepared based on the excellent electrocatalytic activity for the reduction of hydrogen peroxide at the polyethyleneimine-templated silver nanoclusters modified glassy carbon electrode (PEI/AgNCs–GCE). To achieve the optimum electrocatalytic activity for the reduction of hydrogen peroxide, the pH of the buffer solution and concentration of immobilizing AgNCs solution were optimized. Under optimum conditions, the PEI/AgNCs–GCE revealed a highly linear response to H 2 O 2 in the concentration of 10–1440 μmol L −1 with a detection limit of 1.8 μmol L −1 . Compared to some silver nanoparticles modified electrodes, the novel electrochemical sensor based on AgNCs exhibited a better electrocatalytic activity for the reduction of H 2 O 2 and a lower detection limit for the determination of H 2 O 2 .
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HIGH PERFORMANCE POLYMERS
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2015
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IF 1.286
Xia He,Ling-ling Wu,Jia-jun Wang,Tao Zhang,Hui Sun,Ning Shuai
Layer-by-layer (LBL) assembly is an innovative method for fabrication of barrier layer structures on flexible polymers. In this work, two kinds of graphene oxide (GO) multilayer membranes with high barrier properties were prepared by applying LBL on poly(lactic acid) (PLA) films. Nanometer-scale GO multilayer membranes were coated on PLA films and their barrier properties were studied via water vapor and oxygen permeabilities. It turns out that a multilayer (polyethyleneimine (PEI)/GO)n PLA film has excellent oxygen barrier properties, and the oxygen permeability of a four-layer PEI/GO deposition is only 0.98% of the pure PLA film, with unsatisfied water vapor barrier properties. Using PEI/hexadecyltrimethylammonium bromide (CTAB)-modified GO assembling layers on the PLA substrate increased the water contact angle of the multilayer PLA film, and water vapor permeability decreased to 59.25% of the pure PLA film. GO nanosheets with better hydrophobicity can be obtained after being modified by CTAB at the same time, at the expense of partial oxygen barrier properties and transparency. This approach provides a new way to develop multilayer membranes with enhanced barrier performance of PLA films and shows significant interest in packaging applications.
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ANALYTICA CHIMICA ACTA
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2013
·
IF 4.387
Na Zhang,Fei Qu,Hong Qun Luo,Nian Bing Li
In this work, we present a label-free sensor for copper ions. This sensor is composed of silver nanoclusters and cysteine. The fluorescence of the silver nanoclusters was quenched by cysteine, which was recovered in the presence of copper ions. This binding of silver nanoclusters to cysteine promoted agglomeration of silver nanoclusters to yield larger non-fluorescent silver nanoparticles. The presence of copper ions resulted in the oxidation of cysteine to form a disulfide compound, leading to recovery of fluorescence of the silver nanoclusters. The fluorescence of the silver nanoclusters in the presence of cysteine increased with increasing concentration of copper ions in the range of 10–200 nM. The detection limit of this sensor for copper ions was 2.3 nM. The silver nanoclusters–cysteine sensor provides a simple, cost-effective, and sensitive platform for the detection of copper ions.
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SENSORS AND ACTUATORS B-CHEMICAL
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2015
·
IF 4.097
Zhaosheng Qian,Lujing Chai,Cong Tang,Yuanyuan Huang,Jianrong Chen,Hui Feng
This report presents a convenient and reliable fluorometric assay for acetylcholinesterase (AChE) activity and inhibitor screening by taking carbon quantum dots (CQDs) as the signal reporter. The detection mechanism is based on the following facts: (1) the aggregation of CQDs by copper (II) ions results in its fluorescence quenching due to strong coordination of copper ions to carboxyl groups of CQDs; (2) AChE can catalyze the hydrolysis of acetylthiocholine into thiocholine which can induce fluorescence recovery owing to stronger affinity between thiocholine and copper ions; (3) when its inhibitor tacrine is present, AChE loses its catalytic ability for hydrolysis of acetylthiocholine, and thus the fluorescence remains quenched. With this convenient method, the activity of AChE with a concentration as low as 4.25 U/L and a broad linear scope ranging from 14.2 to 121.8 U/L can be assayed, which possesses adequate sensitivity for practical samples of human serum and seminal plasma. The promising application of the proposed method in AChE inhibitor screening was demonstrated. This work expands the application of carbon quantum dots in biological analysis, and provides a new fluorescent assay for AChE activity monitoring and AChE inhibitor screening using a cheaper fluorescent material.
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TALANTA
·
2016
·
IF 4.035
Yating Xu,Ju Liu,Hongyang Zhang,Min Jiang,Lingling Cao,Min Zhang,Wei Sun,Shengli Ruan,Ping Hu
In this study, hypercrosslinked strong cation-exchange polymer resins (HXLPP-SCX) were synthesized and employed as selective sorbents for the solid-phase extraction (SPE) of basic purine metabolites associated with gout. The HXLPP-SCX material was prepared based on hypercrosslinking reactions and sulfonated with concentrated H 2 SO 4 . This synthetic procedure is facile and efficient without using highly toxic reagent. The resulting resins were characterized in the form of monodisperse microspheres (mean diameters of 3‒5 μm) with narrow pore size (2.1 nm) and relatively high specific surface areas (801 m 2 /g). The polymers also possess high ion-exchange capacity (IEC, 2.22 mmol/g) and good adsorption and selectivity performances for basic compounds. The resins used as SPE sorbents permit the selective enrichment of three pivotal purine metabolites (hypoxanthine, xanthine and inosine) in human serum followed by HPLC analysis. Method validation including linearity range, sensitivity, accuracy and reproducibility were evaluated. This method was exemplarily applied in the analysis of serum purines in gout patients and healthy controls. The present results demonstrate a promising potential of this HXLPP-SCX material for the clinical sample pretreatment.
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MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS
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2015
·
IF 2.415
Haibo Mu,Qianjin Liu,Hong Niu,Dongdong Wang,Jiangjiang Tang,Jinyou Duan
Toxic DNA–protein crosslinks (DPCs) can result from exposure to radiation or chemotherapeutic agents. DPCs can also accumulate during aging or stress. However, the cellular mechanisms underlying clearance of DPCs remain largely unknown. Here, we have identified an important role of autophagy in the processing of DPCs induced by three representative agents: formaldehyde, a chemical used widely in industry; UV light; and camptothecin, a cytotoxic anticancer drug. Autophagy inhibitors, 3-methyladenine (3-MA) or chloroquine (CQ), promoted the accumulation of DPCs in damaged cells and injured organs. siRNA-mediated silencing of Atg5 or Atg7, two essential components for the formation of the autophagosome, gave similar results. In contrast, the autophagy inducer rapamycin (RAP) attenuated DPCs in vitro and in vivo . Our findings reveal the importance of autophagy in controlling the level of DPCs, and may open up a new avenue for understanding the formation and clearance of this detrimental DNA adduct.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
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2014
·
IF 3.107
Jian Rong Zhang,Zhong Ling Wang,Fei Qu,Hong Qun Luo,Nian Bing Li
A highly sensitive folic acid (FA) detection method based on the fluorescence quenching of polyethylenimine-capped silver nanoclusters (PEI-AgNCs) was put forward. In the sensing system, FA and PEI-AgNCs were brought into close proximity to each other by electrostatic interaction, and a two-step electron-transfer process, in which the electron was transferred from FA to AgNCs through PEI molecule, led to fluorescence quenching. The fluorescence quenching efficiency of PEI-AgNCs was linearly related to the concentration of FA over the range from 0.1 nM to 2.75 μM. Good linear correlation (R2 = 0.9981) and a detection limit of 0.032 nM were obtained under optimum conditions. Moreover, the proposed method was used for the determination of FA in real samples with satisfactory results, and those coexistent substances could not cause any significant decrease in the fluorescence intensity of AgNCs. Therefore, the proposed research system is of practical significance and application prospects.
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SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
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2014
·
IF 2.129
Peng Wang,Bang Lin Li,Nian Bing Li,Hong Qun Luo
In this contribution, a luminescent gold nanoclusters which were synthesized by bovine serum albumin as novel fluorescent probes were successfully utilized for the determination of d -penicillamine for the first time. Cupric ion was employed to quench the strong fluorescence of the gold nanoclusters, whereas the addition of d -penicillamine caused obvious restoration of fluorescence intensity of the Cu 2+ -gold nanoclusters system. Under optimum conditions, the increment in fluorescence intensity of Cu 2+ -gold nanoclusters system caused by d -penicillamine was linearly proportional to the concentration of d -penicillamine in the range of 2.0 × 10 −5 –2.39 × 10 −4 M. The detection limit for d -penicillamine was 5.4 × 10 −6 M. With the off–on fluorescence signal at 650 nm approaching the near-infrared region, the present sensor for d -penicillamine detection had high sensitivity and low spectral interference. Furthermore, the novel gold nanoclusters-based fluorescent sensor has been applied to the determination of d -penicillamine in real biological samples with satisfactory results.
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