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  • Electrochemiluminescent quaternary Cu-Zn-In-S nanocrystals as a sensing platform: Enzyme-free and sensitive detection of the FLT3 gene based on triple signal amplification
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-21
    Yingying Sun, Xiaohui Wu, Kai Zhang, Qunxiang Ren, Renguo Xie

    A new near-infrared electrochemiluminescence resonance energy transfer (NECL-RET) strategy for enzyme-free amplified DNA detection was designed. In this strategy, the quaternary Cu-Zn-In-S nanocrystals (NCs) were applied as the ECL donor and gold nanostars (AuNSs) were used as the acceptor. The flowerlike MoS2/GO/o-MWNTs nanostructure was synthesized and used as an outstanding substrate to immobilize the NCs. ECL measurements demonstrated that the NCs assembled on the MoS2/GO/o-MWNTs film resulted in ECL intensity amplified by ~2.5-fold compared to that of the NCs assembled directly on the GCE. The Sem used here was not only as a coupling reagent to attach the NCs on the MoS2/GO/o-MWNTs but also as a novel co-reaction accelerator to enhance the ECL intensity. In addition, we designed two hairpin DNA probes of H1 and H2, and based on the target-catalyzed hairpin assembly, tDNA could trigger the hybridization of the H1 and H2-AuNSs to be further released to initiate the next hybridization process to capture a larger number of H2-AuNSs on the electrode surface, which resulted in the quenching of the NCs ECL emission. Therefore, a dramatic increase in the ECL quenching efficiency proportional to the tDNA concentration was achieved. The linear range for tDNA detection was from 10 aM to 10 pM with a detection limit down to 10 aM. This design introduces the new concept of triple signal amplification into ECL determination, and it shows promise to be extended to provide a highly sensitive platform for various target DNA.

    更新日期:2017-09-21
  • Aptamer-based Hydrogel Barcodes for the Capture and Detection of Multiple Types of Pathogenic Bacteria
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-20
    Yueshuang Xu, Huan Wang, Chengxin Luan, Yuxiao Liu, Baoan Chen, Yuanjin Zhao
    更新日期:2017-09-21
  • Gold-loaded nanoporous ferric oxide nanocubes for electrocatalytic detection of microRNA at attomolar level
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-20
    Md. Nazmul Islam, Mostafa Kamal Masud, Nam-Trung Nguyen, Vinod Gopalan, Hatem R. Alamri, Zeid A. Alothman, Md. Shahriar Al Hossain, Yusuke Yamauchi, Alfred King-Yin Lam, Muhammad J.A. Shiddiky

    A crucial issue in microRNA (miRNA) detection is the lack of sensitive method capable of detecting the low levels of miRNA in RNA samples. Herein, we present a sensitive and specific method for the electrocatalytic detection of miR-107 using gold-loaded nanoporous superparamagnetic iron oxide nanocubes (Au@NPFe2O3NC). The target miRNA was directly adsorbed onto the gold surfaces of Au@NPFe2O3NC via gold-RNA affinity interaction. The electrocatalytic activity of Au@NPFe2O3NC was then used for the reduction of ruthenium hexaammine(III) chloride (RuHex, [Ru(NH3)6]3+) bound with target miRNA. The catalytic signal was further amplified by using the ferri/ferrocyanide [Fe(CN)6]3-/4- system. These multiple signal enhancement steps enable our assay to achieve the detection limit of 100 aM which is several orders of magnitudes better than most of the conventional miRNA sensors. The method was also successfully applied to detect miR-107 from cancer cell lines and a panel of tissue samples derived from patients with oesophageal squamous cell carcinoma with excellent reproducibility (% RSD = <5%, for n=3) and high specificity. The analytical accuracy of the method was validated with a standard RT-qPCR method. We believe that our method has the high translational potential for screening miRNAs in clinical samples.

    更新日期:2017-09-20
  • Bifunctional Linker-Based Immunosensing for Rapid and Visible Detection of Bacteria in Real Matrices
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-20
    Youngsang You, Seokwon Lim, Jungwoo Hahn, Young Jin Choi, Sundaram Gunasekaran

    Detection of pathogens present in food and water is essential to help ensure food safety. Among the popular methods for pathogen detection are those based on culture and colony-counting and polymerase chain reaction (PCR). However, the time-consuming nature and/or the need for sophisticated instrumentation of those methods limit their on-site applications. We have developed a rapid and highly sensitive immunosensing method for visible detection of bacteria in real matrices based on the aggregation of AuNPs without requiring any readout device. We use biontinylated anti-bacteria antibodies as bifunctional linkers (BLs) to mediate the aggregation of streptavidin-functionalized gold nanoparticles (st-AuNPs) to produce visually recognizable color change, due to surface plasmon resonance (SPR), which occurs in about 30 min of total assay time when the sample is mildly agitated or within three hours in quiescent conditions. However, the aggregation of st-AuNPs, which produces the indication signal, is achieved very differently than in visual detection methods reported previously and affords ultrahigh sensitivity. While BLs can both bind to the target and crosslink st-AuNPs, their latter function is essentially disabled when they bind to the target bacteria. By varying the amount of st-AuNPs used, we can tailor the assay effectiveness improving limit of detection (LOD) down to 10 CFU mL−1 of E. coli and Salmonella. Test results obtained with tap water, lake water and milk samples show that assay performance is unaffected by matrix effects. Further, in a mixture of live and autoclaved E. coli cells our assay could detect only live cells. Therefore, our BL-based immunosensor is suitable for highly sensitive, rapid, and on-site detection of bacteria in real matrices.

    更新日期:2017-09-20
  • Point-of-care testing for streptomycin based on aptamer recognizing and digital image colorimetry by smartphone
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-20
    Bixia Lin, Ying Yu, Yujuan Cao, Manli Guo, Debin Zhu, Jiaxing Dai, Minshi Zheng

    The rapid detection of antibiotic residual in everyday life is very important for food safety. In order to realize the on-site and visual detection of antibiotic, a POCT method was established by using digital image colorimetry based on smartphone. Streptomycin was taken as the analyte model of antibiotics, streptomycin aptamer preferentially recognized analyte, and the excess aptamer hybridized with the complementary DNA to form the dsDNA. SYBR Green I combined with the dsDNA and then emitted obvious green fluorescence, thus the fluorescence intensity decreased with the increasing of streptomycin concentration. Then a smartphone-based device was constructed as the fluorescence readout. The smartphone camera acquired the images of the fluorescence derived from the samples, and the Touch Color APP installed in smartphone read out the RGB values of the images. There was a linear relationship between the G values and the streptomycin concentrations in the range of 0.1–100 µM. The detection limit was 94 nM, which was lower than the maximum residue limit defined by World Health Organization. The POCT method was applied for determining streptomycin in chicken and milk samples with recoveries in 94.1%-110%. This method had the advantages of good selectivity, simple operation and on-site visualization.

    更新日期:2017-09-20
  • Lipidic Liquid Crystalline Cubic Phases for Preparation of ATP-hydrolysing Enzyme Electrodes
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-20
    Martina Zatloukalova, Ewa Nazaruk, David Novak, Jan Vacek, Renata Bilewicz

    The lipidic liquid-crystalline cubic phase (LCP) is a membrane-mimetic material useful for the stabilization and structural analysis of membrane proteins. Here, we focused on the incorporation of the membrane ATP-hydrolysing sodium/potassium transporter Na+/K+-ATPase (NKA) into a monoolein-derived LCP. Small-angle X-ray scattering was employed for the determination of the LCP structure, which was of Pn3m symmetry for all the formulations studied. The fully characterized NKA-LCP material was immobilized onto a glassy carbon electrode, forming a highly stable enzyme electrode and a novel sensing platform. A typical NKA voltammetric signature was monitored via the anodic reaction of tyrosine and tryptophan residues. The in situ enzyme activity evaluation was based on the ability of NKA to transform ATP to ADP and free phosphate, the latter reacting with ammonium molybdate to form the ammonium phosphomolybdate complex under acidic conditions. The square-wave voltammetric detection of phosphomolybdate was performed and complemented with spectrophotometric measurement at 710 nm. The anodic voltammetric response, corresponding to the catalytic ATP-hydrolysing function of NKA incorporated into the LCP, was monitored at around +0.2 V vs. Ag/AgCl in the presence or absence of ouabain, a specific NKA inhibitor. NKA incorporated into the LCP retained its ATP-hydrolysing activity for 7 days, while the solubilized protein became practically inactive. The novelty of this work is the first incorporation of NKA into a lipidic cubic phase with consequent enzyme functionality and stability evaluation using voltammetric detection. The application of LCPs could also be important in the further development of new membrane protein electrochemical sensors and enzyme electrodes.

    更新日期:2017-09-20
  • Development of a bifunctional nanobiosensor for screening and detection of chemokine ligand in colorectal cancer cell line
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-20
    Saeromi Chung, Pranjal Chandra, Jaseok Peter Koo, Yoon-Bo Shim

    Highly sensitive detection of chemokines in various biological matrices and its interaction with a natural receptor molecule has tremendous importance in cell signaling, medical diagnostics, and therapeutics. In this direction, we have designed the first bifunctional nanobiosensor for chemokine screening and detection in a single experimental setting. The sensor probe was fabricated by immobilizing CXCR2 on the gold nanoparticles (AuNPs) deposited 2,2':5',2''-terthiophene-3' (p-benzoic acid) (TBA) nanocomposite film. The interaction between CXCR2 and chemokines was studied using electrochemical impedance spectroscopy (EIS) and voltammetry. CXCL5 among three ligands showed the strongest affinity to CXCR2, which was further utilized to develop an amperometric CXCL5 biosensor. Analytical parameters, such as CXCR2 receptor concentration, temperature, pH, and incubation time were optimized to obtain the high sensitivity. A dynamic range for CXCL5 detection was obtained between 0.1 and 10 ng/mL with the detection limit of 0.078 ± 0.004 ng/mL (RSD < 4.7%). The proposed biosensor was successfully applied to detect CXCL5 in clinically relevant concentrations in human serum and colorectal cancer cells samples with high sensitivity and selectivity. Interference effect and the stability of the developed biosensor were also evaluated. Method verification was performed by comparing the results using commercially available ELISA kit for CXCL5 detection.

    更新日期:2017-09-20
  • Electrophysiological investigation of human embryonic stem cell derived neurospheres using a novel spike detection algorithm
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-19
    Margot Mayer, Onetsine Arrizabalaga, Florian Lieb, Manuel Ciba, Sylvia Ritter, Christiane Thielemann

    Microelectrode array (MEA) technology in combination with three-dimensional (3D) neuronal cell models derived from human embryonic stem cells (hESC) provide an excellent tool for neurotoxicity screening. Yet, there are significant challenges in terms of data processing and analysis, since neuronal signals have very small amplitudes and the 3D structure enhances the level of background noise. Thus, neuronal signal analysis requires the application of highly sophisticated algorithms. In this study, we present a new approach optimized for the detection of spikes recorded from 3D neurospheres (NS) with a very low signal-to-noise ratio. This was achieved by extending simple threshold-based spike detection utilizing a highly sensitive algorithm named SWTTEO. This analysis procedure was applied to data obtained from hESC-derived NS grown on MEA chips. Specifically, we examined changes in the activity pattern occurring within the first ten days of electrical activity. We further analyzed the response of NS to the GABA receptor antagonist bicuculline. With this new algorithm method we obtained more reliable results compared to the simple threshold-based spike detection.

    更新日期:2017-09-20
  • Target-triggered transcription machinery for ultra-selective and sensitive fluorescence detection of nucleoside triphosphates in one minute
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-19
    Jiantong Dong, Tongbo Wu, Yu Xiao, Lu Chen, Lei Xu, Mengyuan Li, Meiping Zhao

    Nucleoside triphosphates (NTPs) play important roles in living organisms. However, no fluorescent assays are currently available to simply and rapidly detect multiple NTPs with satisfactory selectivity, sensitivity and low cost. Here we demonstrate for the first time a target-triggered in-vitro transcription machinery for ultra-selective, sensitive and instant fluorescence detection of multiple NTPs. The machinery assembles RNA polymerase, DNA template and non-target NTPs to convert the target NTP into equivalent RNA signal sequences which are monitored by the fluorescence enhancement of molecular beacon. The machinery offers excellent selectivity for the target NTP against NDP, NMP and dNTP. Notably, to accelerate the kinetics of the machinery while maintain its high specificity, we investigated the sequence of DNA templates systematically and established a set of guidelines for the design of the optimum DNA templates, which allowed for instant detection of the target NTP at fmol level in less than 1 min. Furthermore, the machinery could be transformed into logic gates to study the coeffects of two NTPs in biosynthesis and real-time monitoring systems to reflect the distribution of NTP in nucleotide pools. These results provide very useful and low-cost tools for both biochemical tests and point-of-care analysis.

    更新日期:2017-09-19
  • Towards a High Throughput Impedimetric Screening of Chemosensitivity of Cancer Cells Suspended in Hydrogel and Cultured in a Paper Substrate
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-19
    Kin Fong Lei, Tai-Kun Liu, Ngan-Ming Tsang

    In order to achieve high predictive value of cell chemosensitivity test for clinical efficacy, cancer cells were suggested to be encapsulated and cultured in hydrogel to mimic the natural microenvironment of tumors. However, handling 3D cells/hydrogel culture construct is tedious and cellular response is difficult to be quantitatively analyzed. In the current study, a novel platform for conducting 3D cell culture and analyzing cell viability has been developed towards a high throughput drug screening. Cells encapsulated in the hydrogel were cultured in the microwells of a paper substrate. The substrate was then immersed in the culture medium containing drug for 2 days. At 24 and 48 h during the culture course, the paper substrate was placed on the measurement electrodes for conducting the impedance measurement in order to quantify the cell viability in the hydrogel. Cell viability of two human hepatoma cell lines (Huh7 and Hep-G2) was quantitatively investigated under the treatment of two drugs (doxorubicin and etoposide). The results represented by IC50 values revealed that Huh7 cells had a higher drug resistance than Hep-G2 cells and doxorubicin had a higher efficacy than etoposide for treating hepatocellular carcinoma. The current work has demonstrated a high throughput, convenient, and quantitative platform for the investigation of chemosensitivity of cells cultured in the 3D environment.

    更新日期:2017-09-19
  • Rapid detection and subtyping of multiple influenza viruses on a microfluidic chip integrated with controllable micro-magnetic field
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-18
    Rui-Qiao Zhang, Shao-Li Hong, Cong-Ying Wen, Dai-Wen Pang, Zhi-Ling Zhang

    Influenza viruses have threatened animals and public health systems continuously. Moreover, there are many subtypes of influenza viruses, which have brought great difficulties to the classification of influenza viruses during any influenza outbreak. So it is crucial to develop a rapid and accurate method for detecting and subtyping influenza viruses. In this work, we reported a rapid method for simultaneously detecting and subtyping multiple influenza viruses (H1N1, H3N2 and H9N2) based on nucleic acid hybridization on a microfluidic chip integrated with controllable micro-magnetic field. H1N1, H3N2 and H9N2 could be simultaneously detected in 80 min with detection limits about 0.21 nM, 0.16 nM, 0.12 nM in order. Moreover, the sample and reagent consumption was as low as only 3 μL. The results indicated that this approach possessed fast analysis and high specificity. Therefore, it is expected to be used to simultaneously subtype and detect multiple targets, and may provide a powerful technique platform for the rapid detection and subtyping analysis of influenza viruses.

    更新日期:2017-09-19
  • Decomposable quantum-dots/DNA nanosphere for rapid and ultrasensitive detection of extracellular respiring bacteria
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-18
    Junlin Wen, Shungui Zhou, Zhen Yu, Junhua Chen, Guiqin Yang, Jia Tang

    Extracellular respiring bacteria (ERB) are a group of bacteria capable of transferring electrons to extracellular acceptors and have important application in environmental remediation. In this study, a decomposable quantum-dots (QDs)/DNA nanosphere probe was developed for rapid and ultrasensitive detection of ERB. The QDs/DNA nanosphere was self-assembled from QDs-streptavidin conjugate (QDs-SA) and Y-shaped DNA nanostructure that is constructed based on toehold-mediated strand displacement. It can release numerous fluorescent QDs-SA in immunomagnetic separation (IMS)-based immunoassay via simple biotin displacement, which remarkably amplifies the signal of antigen-antibody recognizing event. This QDs/DNA-nanosphere-based IMS-fluorescent immunoassay is ultrasensitive for model ERB Shewanella oneidensis, showing a wide detection range between 1.0 cfu/mL and 1.0×108 cfu/mL with a low detection limit of 1.37 cfu/mL. Moreover, the proposed IMS-fluorescent immunoassay exhibits high specificity, acceptable reproducibility and stability. Furthermore, the proposed method shows acceptable recovery (92.4–101.4%) for detection of S. oneidensis spiked in river water samples. The proposed IMS-fluorescent immunoassay advances an intelligent strategy for rapid and ultrasensitive quantitation of low-abundance analyte and thus holds promising potential in food, medical and environmental applications.

    更新日期:2017-09-19
  • Label-free visualization and quantification of single cell activity using metal-clad waveguide (MCWG)-based microscopy
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-18
    Thomas Söllradl, Frederic A. Banville, Ulrike Fröhlich, Michael Canva, Paul G. Charette, Michel Grandbois

    Label-free biosensing methods are very effective for studying cell signaling cascade activation induced by external stimuli. Assays generally involve a large number of cells and rely on the underlying assumption that cell response is homogeneous within a cell population. However, there is an increasing body of evidence showing that cell behavior may vary significantly even among genetically identical cells. In this paper, we demonstrate the use of metal-clad waveguide (MCWG)-based microscopy for label-free real-time monitoring of signaling activity and morphology changes in a small population of cells, with the ability to resolve individual cells. We demonstrate the potential of this approach by quantifying apoptosis-induced intracellular activity in individual cells following exposure to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and by visualizing and quantifying extracellular changes in endothelial cell layer integrity following the activation of the proteinase-activated receptor 1 (PAR1) by thrombin. Results show that averaged signals obtained from a cell population may incorrectly reflect the actual distribution of morphology and kinetics parameters across a cell population by a significant margin.

    更新日期:2017-09-19
  • Recent advances in nanowires-based field-effect transistors for biological sensor applications
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-18
    Rafiq Ahmad, Tahmineh Mahmoudi, Min-Sang Ahn, Yoon-Bong Hahn

    Nanowires (NWs)-based field-effect transistors (FETs) have attracted considerable interest to develop innovative biosensors using NWs of different materials (i.e. semiconductors, polymers, etc.). NWs-based FETs provide significant advantages over the other bulk or non-NWs nanomaterials-based FETs. As the building blocks for FET-based biosensors, one-dimensional NWs offer excellent surface-to-volume ratio and are more suitable and sensitive for sensing applications. During the past decade, FET-based biosensors are smartly designed and used due to their great specificity, sensitivity, and high selectivity. Additionally, they have the advantage of low weight, low cost of mass production, small size and compatible with commercial planar processes for large-scale circuitry. In this respect, we summarize the recent advances of NWs-based FET biosensors for different biomolecule detection i.e. glucose, cholesterol, uric acid, urea, hormone, proteins, nucleotide, biomarkers, etc. A comparative sensing performance, present challenges, and future prospects of NWs-based FET biosensors are discussed in detail.

    更新日期:2017-09-19
  • Enzymatic logic calculation systems based on solid-state electrochemiluminescence and molecularly imprinted polymer film electrodes
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-17
    Wenjing Lian, Jiying Liang, Li Shen, Yue Jin, Hongyun Liu

    The molecularly imprinted polymer (MIP) films were electropolymerized on the surface of Au electrodes with luminol and pyrrole (PY) as the two monomers and ampicillin (AM) as the template molecule. The electrochemiluminescence (ECL) intensity peak of polyluminol (PL) of the AM-free MIP films at 0.7 V vs Ag/AgCl could be greatly enhanced by AM rebinding. In addition, the ECL signals of the MIP films could also be enhanced by the addition of glucose oxidase (GOD)/glucose and/or ferrocenedicarboxylic acid (Fc(COOH)2) in the testing solution. Moreover, Fc(COOH)2 exhibited cyclic voltammetric (CV) response at the AM-free MIP film electrodes. Based on these results, a binary 3-input/6-output biomolecular logic gate system was established with AM, GOD and Fc(COOH)2 as inputs and the ECL responses at different levels and CV signal as outputs. Some functional non-Boolean logic devices such as an encoder, a decoder and a demultiplexer were also constructed on the same platform. Particularly, on the basis of the same system, a ternary AND logic gate was established. The present work combined MIP film electrodes, the solid-state ECL, and the enzymatic reaction together, and various types of biomolecular logic circuits and devices were developed, which opened a novel avenue to construct more complicated bio-logic gate systems.

    更新日期:2017-09-19
  • Processable enzyme-hybrid conductive polymer composites for electrochemical biosensing
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-17
    Yu Liu, Anthony P.F. Turner, Maojun Zhao, Wing Cheung Mak

    A new approach for the facile fabrication of electrochemical biosensors using a biohybrid conducting polymer was demonstrated using glucose oxidase (GOx) and poly (3, 4-ethylenedioxythiophene) (PEDOT) as a model. The biohybrid conducting polymer was prepared based on a template-assisted chemical polymerisation leading to the formation of PEDOT microspheres (PEDOT-MSs), followed by in-situ deposition of platinum nanoparticles (PtNPs) and electrostatic immobilisation of glucose oxidase (GOx) to form water processable GOx-PtNPs-PEDOT-MSs. The morphology, chemical composition and electrochemical performance of the GOx-PtNPs-PEDOT-MS-based glucose biosensor were characterised using scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDS), Fourier transform infrared (FTIR) spectroscopy, zeta potential and electrochemical measurements, respectively. The biosensor delivered a linear response for glucose over the range 0.1 to 10 mM (R2=0.9855) with a sensitivity of 116.25 µA mM−1 cm−2, and limit of detection of 1.55 µM (3×SD/sensitivity). The sensitivity of the developed PEDOT-MS based biosensor is significantly higher (2.7 times) than the best reported PEDOT-based glucose biosensor in the literature. The apparent Michaelis–Menten constant (Kmapp) of the GOx-PtNPs-PEDOT-MS-based biosensors was calculated as 7.3 mM. Moreover, the biosensor exhibited good storage stability, retaining 97% of its sensitivity after 12 days storage. This new bio-hybrid conducting polymer combines the advantages of micro-structured morphology, compatibility with large-scale manufacturing processes, and intrinsic biocatalytic activity and conductivity, thus demonstrating its potential as a convenient material for printed bioelectronics and sensors.

    更新日期:2017-09-19
  • Tetrahedral DNA probe coupling with hybridization chain reaction for competitive thrombin aptasensor
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-15
    Ying-Xu Chen, Ke-Jing Huang, Liu-Liu He, Yi-Han Wang

    A novel competitive aptasensor for thrombin detection is developed by using a tetrahedral DNA (T-DNA) probe and hybridization chain reaction (HCR) signal amplification. Sulfur and nitrogen co-doped reduced graphene oxide (SN-rGO) is firstly prepared by a simple reflux method and used for supporting substrate of biosensor. Then, T-DNA probe is modified on the electrode by Au-S bond and a competition is happened between target thrombin and the complementary DNA (cDNA) of aptamer. The aptamer binding to thrombin forms an aptamer-target conjugate and make the cDNA remained, and subsequently hybridizes with the vertical domain of T-DNA. Finally, the cDNAs trigger HCR, which results in a great current response by the catalysis of horseradish peroxidase to the hydrogen peroxide + hydroquinone system. For thrombin detection, the proposed biosensor shows a wide linearity range of 10–13−10−8 M and a low detection limit of 11.6 fM (S/N=3), which is hopeful to apply in biotechnology and clinical diagnosis.

    更新日期:2017-09-15
  • A novel molecularly imprinted electrochemical sensor based on graphene quantum dots coated on hollow nickel nanospheres with high sensitivity and selectivity for the rapid determination of bisphenol S
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-15
    Hanbing Rao, Xun Zhao, Xin Liu, Ji Zhong, Zhaoyi Zhang, Ping Zou, Yuanyuan Jiang, Xianxiang Wang, Yanying Wang

    In this paper, a novel molecularly imprinted electrochemical sensor (MIECS) based on a glassy carbon electrode (GCE) modified with graphene quantum dots (GQDs) coated on hollow nickel nanospheres (hNiNS) for the rapid determination of bisphenol S (BPS) was proposed for the first time. HNiNS and GQDs as electrode modifications were used to enlarge the active area and electron-transport ability for amplifying the sensor signal, while molecularly imprinted polymers (MIP) film was electropolymerized by using pyrrole as monomer and BPS as template to detect BPS via cyclic voltammetry (CV). Scanning electron microscope (SEM), energy-dispersive spectrometry (EDS), CV and differential pulse voltammetry (DPV) were employed to characterize the fabricated sensor. Experimental conditions, such as molar ratio of monomer to template, electropolymerization cycles, pH, incubation time and elution time were optimized. The DPV response of the MIECS to BPS was obtained in the linear range from 0.1 to 50 μM with a low limit of detection (LOD) of 0.03 μM (S/N = 3) under the optimized conditions. The MIECS exhibited excellent response towards BPS with high sensitivity, selectivity, good reproducibility and stability. In addition, the proposed MIECS was also successfully applied for the determination of BPS in the plastic samples with simple sample pretreatment.

    更新日期:2017-09-15
  • Molecularly imprinted polymeric nanoparticles decorated with Au NPs for highly sensitive and selective glucose detection
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-15
    Wei Zhao, Rongli Zhang, Sheng Xu, Jian Cai, Xiaojie Zhu, Ye Zhu, Wei Wei, Xiaoya Liu, Jing Luo

    A new kind of designed water-compatible molecularly imprinted conductive nanoparticles was prepared by combining macromolecular self-assembly with molecularly imprinting technique. An amphiphilic random copolymer poly(DMA-co-EHA-co-HEA-co-St) containing imino groups and photocrosslinking units was synthesized through free radical copolymerization, which could self-assemble with template molecules (glucose) in aqueous solution to establish nanoparticles embedded with glucose. Meanwhile, AuCl4-, as precursor, was added to generate Au NPs in situ because of reducibility of protonated imino groups, leading to the formation of molecularly imprinted polymeric nanoparticles decorated with Au NPs (Au@MIPNs). By simply adjusting the pH value of the assembly solution, Au@MIPNs with different loading amount of Au NPs could be obtained. Electrodeposition was employed to fabricate a robust integration of MIP film with a transducer, then the film was photo-crosslinked by UV irradiation. After extraction of the template molecules, an MIP sensor modified with Au NPs (Au@MIP sensor) was successfully constructed. The presence of Au NPs greatly improved the conductivity of Au@MIP film and allowed direct electrical connection between the recognition cavities and the transducer, which enhanced the sensitivity of the sensor for templates detection. Effect of Au NPs amount on the performance of the Au@MIP sensor was also evaluated. The obtained Au@MIP sensor demonstrated acceptable selectivity and wider linear ranges (two linear ranges from 10−1° to 10−8 mol L−1 and 10−8 to 10° mol L−1 with a detection limit of 3×10–12 mol L−1) for glucose detection than MIP sensor without decoration of Au NPs.

    更新日期:2017-09-15
  • Functionalized polyacrylamide as an acetylcholinesterase-inspired biomimetic device for electrochemical sensing of organophosphorus pesticides
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-14
    Livia F. Sgobbi, Sergio A.S. Machado

    A plethora of publications has continuously reported electrochemical biosensors for detection of pesticide. However, those devices rarely accomplish commercial application due to technical issues associated with the lack of stability and high cost of the biological recognition element (enzyme). Alternatively, the biomimetic catalysts have arisen as a candidate for application in electrochemical biosensors to overcome the enzymatic drawbacks, combining low cost scalable materials with superior stability. Herein, for the first time, we propose a biomimetic biosensor for organophosphorus pesticide detection employing a functionalized polyacrylamide, polyhydroxamicalkanoate (PHA), which mimics the performance of the acetylcholinesterase (AChE) enzyme. The PHA bears functional groups inserted along its backbone chain working as active sites. Thereby, PHA was immobilized on screen printed electrodes (SPE) through a blend formation with poly(ethylene glycol) methyl ether (mPEG) to prevent its leaching out from the surface. Under optimum conditions, the biomimetic sensor was employed for the amperometric detection of paraoxon-ethyl, fenitrothion and chlorpyrifos ranging from 1.0 and 10.0 μmol L−1 with a limit of detection of 0.36 μmol L−1, 0.61 μmol L−1, and 0.83 μmol L−1, respectively. Typical AChE-based interfering species did not affect the PHA performance, which endorsed its superior behavior. The proposed biomimetic biosensor, denoted as SPE/PHA/mPEG, represents a significant advance in the field, offering a new path for low cost devices by means of an artificial enzyme, simple configuration and superior stability. Moreover, the biosensor performance can be further improved by modifying the electrode surface to enhance electronic transfer rate.

    更新日期:2017-09-15
  • High sensitivity cardiac troponin I detection in physiological environment using AlGaN/GaN High Electron Mobility Transistor (HEMT) Biosensors
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-14
    Indu Sarangadharan, Abiral Regmi, Yen-Wen Chen, Chen-Pin Hsu, Pei-chi Chen, Wen-Hsin Chang, Geng-Yen Lee, Jen-Inn Chyi, Shu-Chu Shiesh, Gwo-Bin Lee, Yu-Lin Wang

    In this study, we report the development of a high sensitivity assay for the detection of cardiac troponin I using electrical double layer gated high field AlGaN/GaN HEMT biosensor. The unique gating mechanism overcomes the drawback of charge screening seen in traditional FET based biosensors, allowing detection of target proteins in physiological solutions without sample processing steps. Troponin I specific antibody and aptamer are used as receptors. The tests carried out using purified protein solution and clinical serum samples depict high sensitivity, specificity and wide dynamic range (0.006–148 ng/ml). No additional wash or sample pre-treatment steps are required, which greatly simplifies the biosensor system. The miniaturized HEMT chip is packaged in a polymer substrate and easily integrated with a portable measurement unit, to carry out quantitative troponin I detection in serum samples with <2 µl sample volume in 5 minutes. The integrated prototype biosensor unit demonstrates the potential of the method as a rapid, inexpensive, high sensitivity CVD biomarker assay. The highly simplified protocols and enhanced sensor performance make our biosensor an ideal choice for point of care diagnostics and personal healthcare systems.

    更新日期:2017-09-14
  • Peptide biosensors for anticancer drugs: Design in silico to work in denaturizing environment
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-14
    Filomena Guida, Anna Battisti, Ivan Gladich, Mauro Buzzo, Elena Marangon, Luciana Giodini, Giuseppe Toffoli, Alessandro Laio, Federico Berti

    One of the main targets in current clinical oncology is the development of a cheap device capable of monitoring in real-time the concentration of a drug in the blood of a patient. This would allow fine-tuning the dosage according to the patient's metabolism, a key condition to reduce side effects. By using surface plasmon resonance and fluorescence spectroscopy we here show that short peptides designed in silico by a recently developed algorithm are capable of binding the anticancer drug irinotecan (CPT-11) with micromolar affinity. Importantly, the recognition takes place in the denaturating solution used in standard therapeutic drug monitoring to detach the drug from the proteins that are present in human plasma, and some of the peptides are capable of distinguishing CPT-11 from its metabolite SN-38. These results suggest that the in silico design of small artificial peptides is now a viable route for designing sensing units, opening a wide range of applications in diagnostic and clinical areas.

    更新日期:2017-09-14
  • Electrochemiluminecence Resonance Energy Transfer System between GNRs and Ru(bpy)32+: Application in Magnetic Aptasensor for β-amyloid
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-14
    Hong Ke, Haifeng Sha, Yinfang Wang, Weiwei Guo, Xin Zhang, Zhiming Wang, Chusen Huang, Nengqin Jia

    Electrochemiluminescent (ECL) assay has gradually drawn increasing interest in the biomedical analysis. This paper proposed a new methodology for ultrasensitive and facile detection of Alzheimer's disease marker β-amyloid (Aβ) by fabricating a sandwich-type ECL sensing platform. Herein, electrochemiluminescence resonance energy transfer (ECL-RET) was employed to determine Aβ concentration, which can be attributed to the quenching effect from RET between Ru(bpy)32+ and gold nanorods (GNRs) acting as ECL-RET electron donor and acceptor, respectively. In this protocol, mesoporous carbon nanospheres were adopted to immobilize ECL reactant Ru(bpy)32+ and antibody via nafion to acquire the RET donor nanocomposites (MOCs/nafion/Ru(bpy)32+/antibody), which were tightly interconnected with epoxy group functionalized Fe3O4 nanoparticles. It is of vital importance that GNRs with exquisite rod shape were synthesized and exhibited a typical absorption peak at 650 nm to quench ECL signal of Ru(bpy)32+ effectively. In addition, the ECL emission decreased linearly with the logarithm of Aβ concentration in a wide linear range from 1.0×10−5 to 100 ng/mL with a detection limit of 4.2×10−6 ng/mL. Furthermore, distinctive and desirable properties were verified to declare the promise for being applicable to analyze the Aβ content in real Alzheimer's cerebrospinal fluid samples with satisfactory results.

    更新日期:2017-09-14
  • A dual marker label free electrochemical assay for Flavivirus dengue diagnosis
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-12
    Adriano Santos, Paulo R. Bueno, Jason J. Davis

    Dengue is a RNA viral illness of the genus Flavivirus which can cause, depending on the pervasiveness of the infection, hemorrhagic dengue fever, known as dengue shock syndrome. Herein we present an electrochemical label free approach enabling the rapid sensitive quantification of NS1 and IgG (a tool supporting an ability to distinguish primary and secondary infections). Using a bifunctional SAM containing PEG moieties and tethered redox thiol, both markers are detectable across clinically relevant levels by label free impedance spectroscopy derived redox capacitance. A subsequent frequency specific immittance function approach enables even more rapid assaying (within seconds) with no impairment of analytical parameters (linearity, sensitivity and variance).

    更新日期:2017-09-12
  • Photoluminescent lateral flow based on non-radiative energy transfer for protein detection in human serum
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-11
    Alejandro Zamora-Gálvez, Eden Morales-Narváez, Javier Romero, Arben Merkoçi
    更新日期:2017-09-11
  • Efficient label-free chemiluminescent immunosensor based on dual functional cupric oxide nanorods as peroxidase mimics
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-09
    Juan Li, Yue Cao, Samuel S. Hinman, Kristy S. McKeating, Yiwen Guan, Xiaoya Hu, Quan Cheng, Zhanjun Yang
    更新日期:2017-09-10
  • Highly sensitive surface plasmon resonance biosensor for the detection of HIV-related DNA based on dynamic and structural DNA nanodevices
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-09
    Wei Diao, Min Tang, Shijia Ding, Xinmin Li, Wenbin Cheng, Fei Mo, Xiaoyu Yan, Hongmin Ma, Yurong Yan

    Early detection, diagnosis and treatment of human immune deficiency virus (HIV) infection is the key to reduce acquired immunodeficiency syndrome (AIDS) mortality. In our research, an innovative surface plasmon resonance (SPR) biosensing strategy has been developed for highly sensitive detection of HIV-related DNA based on entropy-driven strand displacement reactions (ESDRs) and double-layer DNA tetrahedrons (DDTs). ESDRs as enzyme-free and label-free signal amplification circuit can be specifically triggered by target DNA, leading to the cyclic utilization of target DNA and the formation of plentiful double-stranded DNA (dsDNA) products. Subsequently, the dsDNA products bind to the immobilized hairpin capture probes and further combine with DDTs nanostructures. Due to the high efficiency of ESDRs and large molecular weight of DDTs, the SPR response signal was enhanced dramatically. The proposed SPR biosensor could detect target DNA sensitively and specifically in a linear range from 1 pM to 150 nM with a detection limit of 48 fM. In addition, the whole detecting process can be accomplished in 60 min with high accuracy and duplicability. In particular, the developed SPR biosensor was successfully used to analyze target DNA in complex biological sample, indicating that the developed strategy is promising for rapid and early clinical diagnosis of HIV infection.

    更新日期:2017-09-10
  • Synthesis and application of a “plastic antibody” in electrochemical microfluidic platform for oxytocin determination
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-09
    Piyush Sindhu Sharma, Zofia Iskierko, Krzysztof Noworyta, Maciej Cieplak, Pawel Borowicz, Wojciech Lisowski, Francis D'Souza, Wlodzimierz Kutner

    By means of molecular imprinting of a conducting polymer, molecular cavities selective for oxytocin nonapeptide, an autism biomarker, were designed. Embedding of the oxytocin template and then its extracting from the molecularly imprinted polymer (MIP) was confirmed by the XPS analysis. AFM imaging of the MIP film surface indicated changes in mechanical properties of the film after template extraction. The MIP synthetic receptor was deposited by potentiodynamic electropolymerization as a thin film on an Au film electrode in an electrochemical miniaturized microfluidic cell. The use of this cell allowed to shorten analysis time and to decrease the sample volume. The linear dynamic concentration range extended from 0.06 to 1 mM with the limit of detection of 60 µM (S/N=3). Advantageously, sensitivity of the diagnostic microfluidic platform devised for oxytocin determination in both synthetic serum samples and in aqueous solutions was similar, and moreover it was selective to common interferences, such as oxytocin analogs and potential metabolites.

    更新日期:2017-09-10
  • Supramolecular Nano-sniffers for Ultrasensitive Detection of Formaldehyde
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-09
    Uchangi Satyaprasad Akshath, Praveena Bhatt
    更新日期:2017-09-10
  • Biosensing methods for determination of triglycerides: A review
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-09
    CS Pundir, Vinay Narwal

    Triglycerides (TGs) are the major transporters of dietary fats throughout the bloodstream. Besides transporting fat, TGs also act as stored fat in adipose tissue, which is utilized during insufficient carbohydrates supply. TG level is below 150 mg/dL in healthy persons. Elevated TGs level in blood over 500 mg/dL is a biomarker for cardiovascular diseases, Alzheimer disease, pancreatitis and diabetes. Numerous methods are accessible for recognition of TGs, among them, most are cumbersome, time-consuming, require sample pre-treatment, high cost instrumental set-up and experienced personnel to operate. Biosensing approach overcomes these disadvantages, as these are highly specific, fast, easy, cost effective, and highly sensitive. This review article describes the classification, operating principles, merits and demerits of TG biosensors, specifically nanomaterials based biosensors.TG biosensors work ideally within 2.5 to 2700 s, in pH range, 6.0 to 11.0, temperature 25 °C to 39.5 °C and TG concentration range, 0.001 mM to 100 mM,the detection limits being in the range, 0.1 nM to 0.56 mM, with working potential −0.02–1.2 V. These biosensors measured TG level in fruit juices, beverages, sera and urine samples and reused upto 200 times over a period of 7 to 240 days, while stored dry at 4 °C. Future perspective for further improvement and commercialization of TG biosensors are discussed.

    更新日期:2017-09-10
  • Force-activatable biosensor enabling single platelet force mapping directly by fluorescence imaging
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-08
    Yongliang Wang, Dana N LeVine, Margaret Gannon, Yuanchang Zhao, Anwesha Sarkar, Bailey Hoch, Xuefeng Wang

    Integrin-transmitted cellular forces are critical for platelet adhesion, activation, aggregation and contraction during hemostasis and thrombosis. Measuring and mapping single platelet forces are desired in both research and clinical applications. Conventional force-to-strain based cell traction force microscopies have low resolution which is not ideal for cellular force mapping in small platelets. To enable platelet force mapping with submicron resolution, we developed a force-activatable biosensor named integrative tension sensor (ITS) which directly converts molecular tensions to fluorescent signals, therefore enabling cellular force mapping directly by fluorescence imaging. With ITS, we mapped cellular forces in single platelets at 0.4 µm resolution. We found that platelet force distribution has strong polarization which is sensitive to treatment with the anti-platelet drug tirofiban, suggesting that the ITS force map can report anti-platelet drug efficacy. The ITS also calibrated integrin molecular tensions in platelets and revealed two distinct tension levels: 12~54 piconewton (nominal values) tensions generated during platelet adhesion and tensions above 54 piconewton generated during platelet contraction. Overall, the ITS is a powerful biosensor for the study of platelet mechanobiology, and holds great potential in antithrombotic drug development and assessing platelet activity in health and disease.

    更新日期:2017-09-09
  • Highly Selective and Sensitive Sensor Based on an Organic Electrochemical Transistor for the Detection of Ascorbic Acid
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-07
    Lijun Zhang, Guiheng Wang, Di Wu, Can Xiong, Lei Zheng, Yunsheng Ding, Hongbo Lu, Guobing Zhang, Longzhen Qiu
    更新日期:2017-09-08
  • Preparation, characterization and application of urease nanoparticles for construction of an improved potentiometric urea biosensors
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-06
    Seema Jakhar, C.S Pundir

    The nanoparticles(NPs) aggregates of commercial urease from jack beans (Canavalia ensiformis) were prepared by desolvation and glutaraldehyde crosslinking and functionalized by cysteamine dihydrochloride. These enzyme nanoparticles (ENPs) were characterized by transmission electron microscopy (TEM), UV and Fourier transform infrared (FTIR) spectroscopy. The TEM images of urease NPs showed their size in the range, 18–100 nm with an average of 51.2 nm.The ENPs were more active and stable with a longer shelf life than native enzyme molecules. The ENPs were immobilized onto chitosan (CHIT) activated nitrocellulose (NC) membrane via glutaraldehyde coupling with 32.22% retention of initial activity of free ureaseNPs with a conjugation yield of 1.63 mg/cm2.This NC membrane was mounted at the lower/sensitive end of the ammonium ion selective electrode (AISE) with O-ring and then electrode was connected to a digital pH meter to construct a potentiometric urea biosensor. The biosensor exhibited optimum response within 10 s at pH 5.5and 40 °C. The biosensor was employed for measurement of potentiometric determination of urea in sera of apparently healthy and persons suffering from kidney disorders.. The biosensor displayed a low detection limit of 1 µM/L with a wide working range of 2–80 µM/L (0.002–0.08 mM) and sensitivity of 23 mV/decade. The analytical recovery of added urea in serum was 106.33%. The within and between-batch coefficient of variations (CVs) of present biosensor were 0.18% and 0.32% respectively. There was a good correlation (r = 0.99) between sera urea values obtained by reference method (Enzymic colorimetric kit method) and the present biosensor. The biosensor had negligible interference from Na+,K+,NH+4 and Ca2+ but Mg2+,Cu2+ and ascorbic acid but had slight interference, which was overcome by specific ion selective electrode. The ENPs bound NC membrane was used maximally 8–9 times per day over a period of 180 days, when stored in 0.01 M sodium acetate buffer pH 5.5 at 4 °C.

    更新日期:2017-09-07
  • Detection of BCG bacteria using a magnetoresistive biosensor: a step towards a fully electronic platform for tuberculosis point-of-care detection
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-06
    Teresa G. Barroso, Rui C. Martins, Elisabete Fernandes, Susana Cardoso, José Rivas, Paulo P. Freitas

    Tuberculosis is one of the major public health concerns. This highly contagious disease affects more than 10.4 million people, being a leading cause of morbidity by infection. Tuberculosis is diagnosed at the point-of-care by the Ziehl-Nielsen sputum smear microscopy test. Ziehl-Nielsen is laborious, prone to human error and infection risk, with a limit of detection of 104 cells/mL. In resource-poor nations, a more practical test, with lower detection limit, is paramount. This work uses a magnetoresistive biosensor to detect BCG bacteria for tuberculosis diagnosis. Herein we report: i) nanoparticle assembly method and specificity for tuberculosis detection; ii) demonstration of proportionality between BCG cell concentration and magnetoresistive voltage signal; iii) application of multiplicative signal correction for systematic effects removal; iv) investigation of calibration effectiveness using chemometrics methods; and v) comparison with state-of-the-art point-of-care tuberculosis biosensors.Results show a clear correspondence between voltage signal and cell concentration. Multiplicative signal correction removes baseline shifts within and between biochip sensors, allowing accurate and precise voltage signal between different biochips. The corrected signal was used for multivariate regression models, which significantly decreased the calibration standard error from 0.50 to 0.03 log10 (cells/mL). Results show that Ziehl-Nielsen detection limits and below are achievable with the magnetoresistive biochip, when pre-processing and chemometrics are used.

    更新日期:2017-09-07
  • Shifting paradigm of cancer diagnoses in clinically relevant samples based on miniaturized electrochemical nanobiosensors and microfluidic devices
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-05
    Kuldeep Mahato, Ashutosh Kumar, Pawan Kumar Maurya, Pranjal Chandra

    Cancer is one of leading causes of death in the world and occurs in more than two hundred types according to the National Cancer Institute. Its early diagnosis has been remained a prime focus amongst scientists and clinicians since long, not only to understand the complications but also to mitigate its chance of further proliferation. Nowadays, tremendous advances in nanotechnology-empowered diagnostics are serving a substantial input to identify biomarkers associated with various cancers. These biomarkers are found in different forms including overexpressed proteins/surface antigens, metabolites, miRNA, and the entire cell as well. Several approaches have been adopted to detect such cancer biomarkers, where electrochemical sensors have widely been appreciated due to its high sensitivity, selectivity, robustness, and miniaturized point-of-care cancer diagnostics. Due to its immense importance, the present review has been formulated describing classicle concepts of cancer biomarker discovery followed by the recent status of electrochemical biosensors for cancer diagnoses. Particularly, we have summarized the state-of-the-art technologies based on potentiometric, impedimetric, amperometric, voltammetric biosensors for the detection of different biomarkers viz. protein, miRNA, and whole cell and biomarkers generated by metabolic shift in response to carcinoma population. Apart from these, we have also highlighted different deliverable microfluidics-based approaches and recent prototypes for cancer detection. To put various perceptive insights on the recent advancements in cancer diagnostics, an extended table is incorporated, which includes sensor fabrication strategies, type of biomarkers, detection strategies, and analytical performance of the cancer biosensor since last five years (2013–2017).

    更新日期:2017-09-05
  • A label-free cardiac biomarker immunosensor based on phase-shifted microfiber Bragg grating
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-04
    Tong Liu, Li-Li Liang, Peng Xiao, Li-Peng Sun, Yun-Yun Huang, Yang Ran, Long Jin, Bai-Ou Guan
    更新日期:2017-09-04
  • Electrochemical Assay for Continuous Monitoring of Dynamic DNA Methylation Process
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-04
    Li Zhang, Xiaofen Xiao, Yuzhi Xu, Danping Chen, Jun Chen, Yingjun Ma, Zong Dai, Xiaoyong Zou
    更新日期:2017-09-04
  • Effect of HPV16 L1 virus-like particles on the aggregation of non-functionalized gold nanoparticles
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-04
    Giovanni Palomino-Vizcaino, Diana Gabriela Valencia Reséndiz, María Luisa Benítez-Hess, Natalia Martínez-Acuña, Juana Virginia Tapia-Vieyra, Daniel Bahena, Mauricio Díaz-Sánchez, Octavio Patricio García-González, Brenda Arizaí Alvarez-Sandoval, Luis Marat Alvarez-Salas

    Colorimetric assays based on gold nanoparticles (GNPs) are of considerable interest for diagnostics because of their simplicity and low-cost. Nevertheless, a deep understanding of the interaction between the GNPs and the intended molecular target is critical for the development of reliable detection technologies. The present report describes the spontaneous interaction between HPV16 L1 virus-like particles (VLPs) and non-functionalized GNPs (nfGNPs) resulting in the inhibition of nfGNPs salt-induced aggregation and the stabilization of purified VLPs. Ionic-competition experiments suggested that the nature of nfGNPs-VLPs interaction is non-covalent. Adsorption of an RNA aptamer on nfGNPs surface showed an additive aggregation-inhibitory effect. The use of mutant VLPs confirmed that the interaction nfGNPs-VLPs is not mediated by the opposing superficial electrostatic charges, suggesting that non-electrostatic forces participate in the arrangement of nfGNPs on the VLPs surface. Competition experiments using increasing ethanol concentrations on nfGNPs-VLPs complexes suggested hydrophobic interactions as the main stabilizing force. Therefore, the nfGNPs-VLPs interaction described here should facilitate the development of adsorption assays based on nfGNPs for HPV detection and cervical cancer prevention.

    更新日期:2017-09-04
  • A novel immunosensor based on excessively tilted fiber grating coated with gold nanospheres improves the detection limit of Newcastle disease virus ☆
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-01
    Binbin Luo, Yangfei Xu, Shengxi Wu, Mingfu Zhao, Pengjun Jiang, Shenghui Shi, Zhonghao Zhang, Yin Wang, Linlin Wang, Yong Liu
    更新日期:2017-09-04
  • Dendrimer-like amino-functionalized hierarchical porous silica nanoparticle: a host material for 2,4-dichlorophenoxyacetic acid imprinting and sensing
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-09-01
    Hongmei Wang, Qin Xu, Juan Wang, Wei Du, Fengping Liu, Xiaoya Hu

    In this work, a novel molecularly imprinted electrochemical sensor based on the amino-functionalized silica nanoparticles was built for the sensitive and selective detection of 2,4-dichlorophenoxyacetic acid (2,4-D). The hierarchical porous dendrimer-like silica nanoparticles (HPSNs-NH2) were synthesized by an ethyl ether emulsion method. The selective molecularly imprinted polymers (MIP) was prepared on the HPSNs-NH2 modified electrode via electropolymerization by using 2,4-D as the template and o-phenylenediamine (OPD) as the monomer. The porous structure of HPSNs-NH2 reduced the diffusion limitations of the analytes, enhanced the accessibility and increased the surface area of the sensor, while the MIP layer offered the ability to recognize and quantify target 2,4-D by using ferro/ferricyanide as probes. Several significant experimental parameters on the analytical performance of the MIP/HPSNs-NH2 sensor were explored and optimized. Under the optimized condition, the sensor displayed an appreciable selectivity over structurally related compounds and good sensitivity toward 2,4-D. The linear range of 2,4-D detection was from 1.00×10−10 to 2.50×10−8 M and the detection limit was down to 1.17×10–11 M according to the 3Sa/b criteria. This method has been applied to detect 2,4-D in bean sprout samples with satisfying results.

    更新日期:2017-09-04
  • Broccoli-shaped Biosensor Hierarchy for Electrochemical Screening of Noradrenaline in Living Cells
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-08-31
    M.Y. Emran, M. Mekawy, N. Akhtar, M.A. Shenashen, I.M. EL-Sewify, A. Faheem, S.A. El-Safty

    Monitoring and determination of ultra-trace concentrations of monoamine neurotransmitter such as noradrenaline (NA) in living cells with simple, sensitive and selective assays are significantly interesting. We design NA-electrode sensing system based on C-, N-doped NiO broccoli-like hierarchy (CNNB). The spherical broccoli-head umbrella architectures associated with nano-tubular arrangements enabled to tailor NA biosensor design. The homogenous doping and anisotropic dispersion of CN nanospheres along the entire NB head nanotubes lead to creating of abundant electroactive sites in the interior tubular vessels and outer surfaces for ultrasensitive detection of NA in living cells such as PC12. The CNNB biosensor electrodes showed efficient electrocatalytic activity, enhanced kinetics for electrooxidation of NA, and fast electron-transfer between electrode–electrolyte interface surfaces, enabling synergistic enhancement in sensitivity, and selectivity at a low-detectable concentration of ∼ 6 nM and reproducibility of broccoli-shaped NA-electrodes. The integrated CNNB biosensor electrodes showed evidence of monitoring and screening of NA released from PC12 cells under K+ ion-extracellular stimulation process. The unique features of CNNB in terms of NA-selectivity among multi-competitive components, long-term stability during the detection of NA may open their practical, in-vitro application for extracellular monoamine neurotransmitters detection in living cells.

    更新日期:2017-09-04
  • Novel Amine-Functionalized Iron Trimesates with Enhanced Peroxidase-Like Activity and their Applications for the Fluorescent Assay of Choline and Acetylcholine
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-08-30
    Anil H. Valekar, Bhagwan S. Batule, Moon Il Kim, Kyung-Ho Cho, Do-Young Hong, U-Hwang Lee, Jong-San Chang, Hyun Gyu Park, Young Kyu Hwang

    We herein describe novel amine-grafted metal–organic frameworks (MOFs) as a promising alternative to natural peroxidase enzyme and their applications for a fluorescent assay of choline (Cho) and acetylcholine (ACh). Among diverse amine-functionalized MOFs, N,N,N′,N′-tetramethyl-1,4-butanediamine (TMBDA)-functionalized MIL-100(Fe) (TMBDA-MIL-100(Fe)) exhibited the highest peroxidase activity by developing intense fluorescence from Amplex UltraRed (AUR) in the presence of H2O2, which was presumably due to the synergetic effect of the enhanced negative potential and precisely controlled molecular size of the grafted diamine. Based on the excellent peroxidase-like activity of TMBDA-MIL-100(Fe), choline and ACh were reliably determined down to 0.027 and 0.036 µM, respectively. Furthermore, practical applicability of this strategy was successfully demonstrated by detecting choline and ACh in spiked samples of milk and serum, respectively. This work highlights the advantages of amine-grafted MOFs for the preparation of biomimetic catalysts, extending their scope to biosensor applications.

    更新日期:2017-08-31
  • Recent advances and future prospects in molecularly imprinted polymers-based electrochemical biosensors
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-08-30
    Rijun Gui, Hui Jin, Huijun Guo, Zonghua Wang

    Molecularly imprinted polymers (MIPs)-based electrochemical biosensors (ECBSs) have many advantages from MIPs and ECBSs, such as high selectivity and sensitivity, chemical/mechanical stability, reusability, low limit of detection, facile preparation and low cost. MIPs-based ECBSs attract much attention in medical diagnose, biological analysis, environmental monitoring, food safety evaluation, etc. Due to the capacity of highly specific recognition for target biomolecules, MIPs-based ECBSs have been smartly designed and extensively used for electrochemical sensing applications in recent years, exhibiting obvious superiority over other analytical techniques. In this review, firstly we systematically summarize the recent advances of MIPs-based ECBSs reported in recent years, referring to the preparation, structures and components of sensing systems. Secondly, we highlight the sensing applications for various significant biomolecules (proteins, antibiotics, pesticide, neurotransmitter, hormone, etc.), and demonstrate the sensing mechanism and detection performance. Finally, the rational summaries, present challenges and future prospects in the field of MIPs-based ECBSs have been discussed reasonably.

    更新日期:2017-08-31
  • A specific nanoprobe for cysteine based on nitrogen-rich fluorescent quantum dots combined with Cu2+
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-08-30
    Tingting Gu, Wu Zou, Fuchun Gong, Jiaoyun Xia, Can Chen, Xuejiao Chen

    As a new member of the carbon quantum-dot family, fluorescent nitrogen-rich quantum dots (NRQDs) were prepared by a mixed solvothermal method using 2-azidoimidazole and aqueous ammonia as reactants. These NRQDs are rich in nitrogen up to 40.2%, which are endowed with high fluorescence quantum yield, good photostability, water-solubility and favourable biocompatibility. We further explored the use of NRQDs combined with Cu2+ as a nanoprobe for sensing fluorescently of cysteine (Cys) in complex biological samples. In this sensing system, the fluorescence is significantly quenched via energy transfer from NRQDs to Cu2+ for the coordination of amino-containing groups with Cu2+. The strong affinity between Cu 2+ and Cys leads to the formation of Cu2+-Cys complexes and cause the detachment of Cu2+ from the surface of NRQDs, thus the fluorescence of NRQDs recover. This nanoprobe allows analysis of Cys by modulating the switch of the fluorescence of NRQDs with a detection limit of 5.3 nM. As expected, the proposed NRQDs-Cu2+complex-based nanoprobes were successfully applied for the determination of Cys in human serum and plasma samples with recoveries ranging from 97.2% to 105.7%. The probe ensemble was also successfully applied to imaging of Cys in living cells with satisfactory results, which shows strong potential for clinical diagnosis.

    更新日期:2017-08-31
  • A novel psychoanalytical approach: an electrochemical ligand-binding assay to screen antipsychotics
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-08-30
    Tugba Kilic, Valerie Brunner, Laurent Audoly, Sandro Carrara

    Schizophrenia treatment may see a paradigm shift due to development of new atypical antipsychotic drugs (APDs), with better tolerability due to more selective dopamine (DA) receptor blockade. Monitoring of these APD candidates in biological fluids is of great importance to reduce the development cost, to clarify the mechanism of action and ultimately to support the demonstration of efficacy of these molecules. Electrochemical approaches have attracted great attention for monitoring DA and APD levels but none of the methods developed so far aimed to screen APD candidates. Herein, by this work, we propose for the first time an electrochemical ligand-binding approach for antipsychotic drug screening where competitive binding of a novel APD and DA to a dopamine D3 receptor (D3R) was investigated by looking at electrochemical signals of DA and drug before and after D3R interaction. D3R peptide was incubated with DA and/or drug first and then changes in electrochemical oxidation signals of free DA and the drug was measured by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Circular Dichroism (McDevitt et al.) spectroscopy was used to investigate the secondary structure of the peptide upon binding with either drug and/or DA.

    更新日期:2017-08-31
  • Sensitive electrochemiluminescent immunosensor for diabetic nephropathy analysis based on tris(bipyridine) ruthenium(II) derivative with binary intramolecular self-catalyzed property
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-08-26
    Haijun Wang, Yaqin Chai, Hang Li, Ruo Yuan

    Electrochemiluminescence (ECL) co-reaction and ECL resonance energy transfer (ECL-RET) are two main methods for enhancing the ECL efficiency. In this work, a novel tris(bipyridine) ruthenium(II) derivative (Ru(bpy)2(mcbpy)2+-PEI-ABEI) with high ECL efficiency due to the binary intramolecular ECL self-catalyzed property including intramolecular co-reaction and intramolecular ECL-RET, was prepared for the construction of immunosensor. Firstly, through intramolecular co-reaction, polyethyleneimine (PEI) with large amount of amine co-reactive groups (primary, secondary and tertiary amine) not only increased the ECL intensity of Ru(bpy)2(mcbpy)2+, but also improved the ECL signal of N-(aminobutyl)-N-(ethylisoluminol) (ABEI). Meanwhile, ABEI, as an effective energy transfer donor, could further increase the ECL intensity of Ru(bpy)2(mcbpy)2+ (as energy transfer receptor) by intramolecular ECL-RET. It is worth noting that the strategy combined intramolecular co-reaction and intramolecular ECL-RET in the same ECL process was more effective for ECL efficiency enhancement compared with the traditional intermolecular interaction or individual intramolecular interaction, which would improve the sensitivity of immunosensor obviously. Thus, the proposed signal-on ECL immunosensor using convex hexoctahedral Pd@Au core-shell nanocrystals (Pd-Au HCDs) as immobilized platform exhibited a detected range for collagen type IV (Col IV), a typical biomarker of diabetic nephropathy (DN), from 0.5 pg mL−1 to 7.2 ng mL−1 with an estimated detection limit of 0.17 pg mL−1. The developed strategy combined intramolecular co-reaction with intramolecular ECL-RET offered an effective mean for ECL methodology in ECL efficency enhancement and also provided possible road for early diagnosis and treatment monitoring of DN.

    更新日期:2017-08-28
  • Nitrogen-doped graphene quantum dot for direct fluorescence detection of Al3+ in aqueous media and living cells
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-08-26
    Bi-Yun Fang, Cheng Li, Yuan-Yang Song, Fang Tan, Yuan-Cheng Cao, Yuan-Di Zhao

    Graphene quantum dot (GQD) has been attractive in analytical science field due to its low toxicity, stable photoluminenscence. Herein, nitrogen-doped GQD (N-GQD) was prepared by a facile solvothermal treatment of GO using dimethylformamide, and exhibited a green emission with 23.1% quantum yield. The N-GQD probe showed a selective and sensitive fluorescence enhancement response to Al3+, the mechanism might be the formation of a complex between Al3+ and N-GQD constrained the photo-induced electron transfer (PET) process of N-GQD itself. With Benesi-Hildebrand equation, the binding constant and molar ratio between N-GQD and Al3+ was calculated to be 4.6 × 104 L mol−1 and 1:1 respectively. The pKa walue of N-GQD was also determined to be 4.4 by capillary electrophoresis. In pH 4.0 PBS solution, there was a good linear relation between the fluorescence intensity and the logarithm of concentration of Al3+ in the range of 2.5 −75 μmol L−1, the limit of detection (3σ) was 1.3 μmol L−1. This “Off - On” fluorescence method had been applied to accurate quantification of aluminum in hydrotalcite tablets. What's more, the fluorescence switch property of N-GQD was explored by alternate addition of Al3+ and EDTA. The probe was also utilized for detection Al3+ in living cells due to its excellent biocompatibility.

    更新日期:2017-08-28
  • Confocal Epifluorescence Sensor with an Arc-shaped Aperture for Slide-based PCR Quantification
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-08-24
    Jui-Hong Weng, Lin-Chi Chen
    更新日期:2017-08-25
  • Novel Graphene-Based Biosensor for Early Detection of Zika Virus Infection
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-08-24
    Savannah Afsahi, Mitchell B. Lerner, Jason M. Goldstein, Joo Lee, Xiaoling Tang, Dennis A. Bagarozzi Jr., Deng Pan, Lauren Locascio, Amy Walker, Francie Barron, Brett R. Goldsmith
    更新日期:2017-08-24
  • Construction of an ultrasensitive non-enzymatic sensor to investigate the dynamic process of superoxide anion release from living cells
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-08-24
    Hongwei Wei, Tianyi Shang, Tiaodi Wu, Guoan Liu, Lan Ding, Xiuhui Liu

    In this work, a novel non-enzymatic superoxide anion (O2•−) sensor was constructed based on Ag nanoparticles (NPs) / poly (amidoamine) (PAMAM) dendrimers and used to investigate the dynamic process of O2•− release from living cells. The AgNPs/PAMAM nanohybrids were characterized by transmission electron microscopy (TEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The fabricated electrode exhibited excellent catalytic activity toward the reaction of O2•− with a super low detection limit (LOD) of 2.530×10–13 M (S/N=3) and wide linear range of 8 orders of magnitude. It could fulfill the requirement of real-time measurement O2•− released from living cells. Furthermore, zymosan was chosen as the stimulant to induce O2•− generation from cancer cells (rat adrenal medulla pheochromocytoma cell (PC12)). The electrochemical experiment results indicated that the levels of intracellular O2•− depended on the amount of Zymosan. A large amount of O2•− generated in the living cells by added heavy stimulant could damage cells seriously. More importantly, a vitro simulation experiment confirmed the role of superoxide dismutase (SOD) for the first time because it could maintain the O2•− concentration at a normal physiological range. These findings are of great significance for evaluating the metabolic processes of O2•− in the biological system, and this work has the tremendous potential application in clinical diagnostics to assess oxidative stress.

    更新日期:2017-08-24
  • Trimetallic Pd@Au@Pt nanocomposites platform on -COOH terminated reduced graphene oxide for highly sensitive CEA and PSA biomarkers detection
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-08-24
    S.C. Barman, M.F. Hossain, Hyosang Yoon, Jae Y. Park

    In this paper, a trimetallic Pd@Au@Pt nanocomposites platform on -COOH terminated reduced graphene oxide (COOH-rGO) was newly developed for sensing carcinoembryonic antigen (CEA) and prostate specific antigen (PSA) biomarkers. Trimetallic electro-catalytic surfaces were prepared by the electrodeposition of noble metals (Pd@Au@Pt) nanoparticles on COOH- rGO. After EDC/NHS treatment, the anti-CEA and anti-PSA were immobilized separately on two different platforms. Under optimized conditions, the platforms were analyzed by cyclic voltammetry and differential pulse voltammetry (DPV). The platform shows good electro catalytic activity, high sensitivity, and acceptable stability for sensing CEA and PSA biomarkers. For CEA, we obtained sensitivity of 0.099 ± 0.007 µA ng−1 mL, wide linear range from 12 pg ml−1 to 85 ng ml−1 and a limit of detection (LOD) of 8 pg ml−1, while for PSA sensitivity is 0.267 ± 0.02 µA ng −1 mL, wide linear range from 3 pg ml−1 to 60 ng ml−1 and LOD of 2 pg ml−1. The validation of the platform was observed through standard addition method. Thus, the sensing platform could be used for the point of care detection of CEA and PSA.

    更新日期:2017-08-24
  • Inner filter with carbon quantum dots: a selective sensing platform for detection of hematin in human red cells
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-08-24
    Qian Qian Zhang, Bin Bin Chen, Hong Yan Zou, Yuan Fang Li, Cheng Zhi Huang

    Hematin plays a crucial role in various physiological functions, and the determination of hematin in complex biological matrixes is a significant but difficult issue. Considering the unique photophysical/photochemical properties of carbon quantum dots (CQDs) prepared with p-aminobenzoic acid (PABA) and ethanol, a new strategy for the design of fluorescent probes for hematin has been achieved. The proposed sensor array is fabricated based on the inner filter effect (IFE) between hematin and CQDs with phenomenon of selective fluorescence quenching of CQDs which results from the strong absorption of the excitation and emission spectrum of CQDs by hematin. The fluorescence quenching of CQDs is closely related to the amount of hematin and there is a good linear relationship over the range of 0.5 μM–10 μM with a detection limit of 0.25 μM. What's more, the fluorescence assay has been successfully applied for hematin sensing in healthy human red cells showing this sensing assay has a great potential prospect for detection of hematin in the complex matrixes.

    更新日期:2017-08-24
  • Quantification of viable and non-viable Legionella spp. by heterogeneous asymmetric recombinase polymerase amplification (haRPA) on a flow-based chemiluminescence microarray
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-08-24
    Catharina Kober, Reinhard Niessner, Michael Seidel

    Increasing numbers of legionellosis outbreaks within the last years have shown that Legionella are a growing challenge for public health. Molecular biological detection methods capable of rapidly identifying viable Legionella are important for the control of engineered water systems. The current gold standard based on culture methods takes up to 10 days to show positive results. For this reason, a flow-based chemiluminescence (CL) DNA microarray was developed that is able to quantify viable and non-viable Legionella spp. as well as Legionella pneumophila in one hour. An isothermal heterogeneous asymmetric recombinase polymerase amplification (haRPA) was carried out on flow-based CL DNA microarrays. Detection limits of 87 genomic units (GU) µL−1 and 26 GU µL−1 for Legionella spp. and Legionella pneumophila, respectively, were achieved. In this work, it was shown for the first time that the combination of a propidium monoazide (PMA) treatment with haRPA, the so-called viability haRPA, is able to identify viable Legionella on DNA microarrays. Different proportions of viable and non-viable Legionella, shown with the example of L. pneumophila, ranging in a total concentration between 101 to 105 GU µL−1 were analyzed on the microarray analysis platform MCR 3. Recovery values for viable Legionella spp. were found between 81 and 133%. With the combination of these two methods, there is a chance to replace culture-based methods in the future for the monitoring of engineered water systems like condensation recooling plants.

    更新日期:2017-08-24
  • NANOSTRUCTURED MATERIALS WITH PLASMONIC NANOBIOSENSORS FOR EARLY CANCER DETECTION: A PAST AND FUTURE PROSPECT
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-08-24
    Sathish Sugumaran, Mohd Faizal Jamlos, Mohd Noor Ahmad, Chandar Shekar Bellan, Dominique Schreurs
    更新日期:2017-08-24
  • Electrochemiluminescent resonance energy transfer of polymer dots for aptasensing
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-08-23
    Feng Sun, Ziyu Wang, Yaqiang Feng, Yixiang Cheng, Huangxian Ju, Yiwu Quan

    This work designed a three-component polymer for the preparation of polymer dots (Pdots). The polymer contained 9-(diphenylmethylene)−9H-fluorene (DPF), 9,9-dioctyl-9H-fluorene (DOF) and 1,1’-binaphthyl moieties, and was synthesized via Pd-catalyzed Suzuki reaction. It exhibited obvious yellow-colored aggregation-induced emission (AIE) for fluorescence enhancement at 543 nm via an intramolecular fluorescence resonance energy transfer from DOF moiety to DPF moiety. The Pdots prepared by nanoprecipitation could be conveniently cast on electrode surface and showed a stable anodic electrochemiluminescence (ECL) emission in the presence of triethylamine as a co-reactant. The ECL emission could be effectively quenched by rhodamine B via resonance energy transfer, which led to an “off-on” switch for the design of ECL sensing methodology. Using Pb2+ as a target model, an ECL aptasensor for the detection of trace Pb2+ was proposed, which showed a linear range of 100 pM to 1.0 μM with a detection limit down to 38.0 pM. This work demonstrated the first Pdots prepared with AIE-active polymer for highly efficient ECL sensing.

    更新日期:2017-08-23
  • Novel Ratiometric Surface-Enhanced Raman Spectroscopy Aptasensor for Sensitive and Reproducible Sensing of Hg2+
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-08-19
    Yan Wu, Tingting Jiang, Zhaoyang Wu, Ruqin Yu

    It is important to precisely monitor mercury (II) ions (Hg2+) for environment protection and human health monitoring. Although many strategies have been developed in the past decades, there still remains a challenge for developing an ultrasensitive, simple and reliable approach to detect Hg2+. Herein, we report a ratiometric surface-enhanced Raman scattering (SERS) aptasensor by employing aptamer-modified Au@Ag core-shell nanoparticles (Au@Ag NPs) as highly functional sensing probes, allowing for ultrasensitive detection of Hg2+. In principle, the thiolated 5’-Cy3 labeled aptamer probe (Cy3-aptamer) is firstly immobilized on the SERS substrate surface and then hybridizes with the 5’-Rox labeled complementary DNA (cDNA) to form a rigid double-stranded DNA (dsDNA), in which the Cy3 and Rox Raman labels are used to produce the ratiometric Raman signals. In the presence of Hg2+, the aptamer DNA turns into the thymine (T)-Hg2+-T mediated hairpin structure, leading to the dissociation of dsDNA. As a result, the Rox labels are away from the Au@Ag NP SERS substrate while Cy3 labels are close to it. Therefore, the intensity of SERS signal from Cy3 labels increases while that from Rox labels decreases. The ratio between the Raman intensities of Cy3 labels and Rox labels is linear with Hg2+ concentrations in the range from 0.001 nM to 1.0 nM, and the limit of detection is estimated to 0.4 pM. The proposed strategy provides a new rapid, simple and reliable approach for sensitive detection of Hg2+ and may create a universal methodology for developing analogous aptasensors for a wide range of other analytes determination.

    更新日期:2017-08-19
  • Rapid and label-free electrochemical DNA biosensor for detecting Hepatitis A virus
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-08-19
    Marisa Manzano, Sara Viezzi, Sandra Mazerat, Robert S. Marks, Jasmina Vidic

    Diagnostic systems that can deliver highly specific and sensitive detection of hepatitis A virus (HAV) in food and water are of particular interest in many fields including food safety, biosecurity and control of outbreaks. Our aim was the development of an electrochemical method based on DNA hybridization to detect HAV. A ssDNA probe specific for HAV (capture probe) was designed and tested on DNAs from various viral and bacterial samples using Nested-Reverse Transcription Polymerase Chain Reaction (nRT-PCR). To develop the electrochemical device, a disposable gold electrode was functionalized with the specific capture probe and tested on complementary ssDNA and on HAV cDNA. The DNA hybridization on the electrode was measured through the monitoring of the oxidative peak potential of the indicator tripropylamine by cyclic voltammetry. To prevent non-specific binding the gold surface was treated with 3% BSA before detection. High resolution atomic force microscopy (AFM) confirmed the efficiency of electrode functionalization and on-electrode hybridization. The proposed device showed a limit of detection of 0.65 pM for the complementary ssDNA and 6.94 fg/μL for viral cDNA. For a comparison, nRT-PCR quantified the target HAV cDNA with a limit of detection of 6.4 fg/µL. The DNA-sensor developed can be adapted to a portable format to be adopted as an easy-to- use and low cost method for screening HAV in contaminated food and water. In addition, it can be useful for rapid control of HAV infections as it takes only a few minutes to provide the results.

    更新日期:2017-08-19
  • Recent advances in signal amplification strategy based on oligonucleotide and nanomaterials for microRNA detection-a review
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-08-18
    Ying-Xu Chen, Ke-Jing Huang, Ke-Xin Niu

    MicroRNAs (MiRNAs) play multiple crucial regulating roles in cell which can regulate one third of protein-coding genes. MiRNAs participate in the developmental and physiological processes of human body, while their aberrant adjustment will be more likely to trigger diseases such as cancers, kidney disease, central nervous system diseases, cardiovascular diseases, diabetes, viral infections and so on. What's worse, for the detection of miRNAs, their small size, high sequence similarity, low abundance and difficult extraction from cells impose great challenges in the analysis. Hence, it's necessary to fabricate accurate and sensitive biosensing platform for miRNAs detection. Up to now, researchers have developed many signal-amplification strategies for miRNAs detection, including hybridization chain reaction, nuclease amplification, rolling circle amplification, catalyzed hairpin assembly amplification and nanomaterials based amplification. These methods are typical, feasible and frequently used. In this review, we retrospect recent advances in signal amplification strategies for detecting miRNAs and point out the pros and cons of them. Furthermore, further prospects and promising developments of the signal-amplification strategies for detecting miRNAs are proposed.

    更新日期:2017-08-18
  • Thiourea sensor development based on hydrothermally prepared CMO nanoparticles for environmental safety
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-08-18
    Mohammed M. Rahman, Jahir Ahmed, Abdullah M. Asiri

    Low-dimensional cobalt oxide codoped manganese oxide nanoparticles (CMO NPs; dia. ~25.6 nm) were synthesized using the hydrothermal method in alkaline phase. The optical, morphological, and structural properties of CMO NPs were characterized in details using FT-IR, UV/vis., FESEM, XEDS, XPS, TEM, and XRD techniques. Glassy carbon electrode (GCE) was fabricated with a thin-layer of CMO NPs by conducting coating binders for the development of selective and sensitive thiourea (TU) sensors. Electrochemical responses along with higher sensitivity, large-dynamic-range, and long-term stability towards TU were performed by electrochemical I-V approach. The calibration curve was found linear over a wide linear dynamic range (LDR) of TU concentration. From the gradient of the calibration plot, limit of detection (LOD), and sensitivity were calculated as 12.0 ± 0.05 pM and 3.3772 nAnM-1cm-2 respectively. It is an organized route for the development of chemical sensor based on very low-dimensional CMO NPs/GCE using electrochemical reduction phenomena. As far as we know, this report is the maiden publication on highly sensitive TU sensor based on the CMO NPs/GCE. This method could be a pioneer developer in TU sensitive chemical sensor development using doped NPs in the simple I-V method for the important sensor applications with useful doped materials coupled nano-technological systems for environmental safety.

    更新日期:2017-08-18
  • Xanthine oxidase functionalized Ta2O5 nanostructures as a novel scaffold for highly sensitive SPR based fiber optic xanthine sensor
    Biosens. Bioelectron. (IF 7.780) Pub Date : 2017-08-18
    Ravi Kant, Rana Tabassum, Banshi D. Gupta

    Fabrication and characterization of a surface plasmon resonance based fiber optic xanthine sensor using entrapment of xanthine oxidase (XO) enzyme in several nanostructures of tantalum (v) oxide (Ta2O5) have been reported. Chemical route was adopted for synthesizing Ta2O5 nanoparticles, nanorods, nanotubes and nanowires while Ta2O5 nanofibers were prepared by electrospinning technique. The synthesized Ta2O5 nanostructures were characterized by photoluminescence, scanning electron microscopy, UV-Visible spectra and X-ray diffraction pattern. The probes were fabricated by coating an unclad core of the fiber with silver layer followed by the deposition of XO entrapped Ta2O5 nanostructures. The crux of sensing mechanism relies on the modification of dielectric function of sensing layer upon exposure to xanthine solution of diverse concentrations, reflected in terms of shift in resonance wavelength. The sensing probe coated with XO entrapped Ta2O5 nanofibers has been turned out to possess maximum sensitivity amongst the synthesized nanostructures. The probe was optimized in terms of pH of the sample and the concentration of XO entrapped in Ta2O5 nanofibers. The optimized sensing probe possesses a remarkably good sensitivity of 26.2 nm/µM in addition to linear range from 0 to 3 µM with an invincible LOD value of 0.0127 µM together with a response time of 1 min. Furthermore, probe selectivity with real sample analysis ensure the usage of the sensor for practical scenario. The results reported open a novel perspective towards a sensitive, rapid, reliable and selective detection of xanthine.

    更新日期:2017-08-18
Some contents have been Reproduced with permission of the American Chemical Society.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.
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