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Talanta
Pergamon Press
Talanta

Pergamon Press

0039-9140

Talanta/Journal TalantaSCIISTPEIAHCI
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    Ligand-protected nanoclusters and their role in agriculture, sensing and allied applications

    Aparna, AsokSreehari, H.Chandran, AmruthaAnjali, K. P....
    17页
    查看更多>>摘要：Nano biotechnology, when coupled with green chemistry, can revolutionize human life because of the vast opportunities and benefits it can offer to the quality of human life. Luminescent metal nanoclusters (NCs) have recently developed as a potential research area with applications in different areas like medical, imaging, sensing etc. Recently these new candidates have proved to be beneficial in the food supply chain enabling controlled release of nutrients, pesticides and as nanosensors for the detection of contaminants and play roles in healthy food storage and maintaining food quality. An assortment of nanomaterials has been employed for these applications and reviews have been published on the use of nanotechnology in agriculture. Ligand-protected metal nanoclusters are a distinctive class of small organic-inorganic nanostructures that garnered immense research interest in recent years owing to their stability at specific "magic size" compositions along with tunable properties that make them promising candidates for a wide range of nanotechnology-based applications. This review tries to consolidate the recent developments in the area of ligand-protected nanoclusters in connection with the detection of pesticides, food contaminants, heavy metal ions and plant growth monitoring for healthy agricultural practices. Its antimicrobial activity to manage the microbial contamination is highlighted. The review also throws light on the various perspectives by which food production and allied areas will be transformed in future.
      原文链接:
    • NSTL
    • Elsevier

    Novel electrochemiluminescent assay for the aptamer-based detection of testosterone

    Canovas, RocioDaems, EliseCampos, RuiSchellinck, Sofie...
    11页
    查看更多>>摘要：This work presents a proof-of-concept assay for the detection and quantification of small molecules based on aptamer recognition and electrochemiluminescence (ECL) readout. The testosterone-binding (TESS.1) aptamer was used to demonstrate the novel methodology. Upon binding of the target, the TESS.1 aptamer is released from its complementary capture probe - previously immobilized at the surface of the electrode - producing a decrease in the ECL signal after a washing step removing the released (labeled) TESS.1 aptamer. The analytical capability of the ECL assay towards testosterone detection was investigated displaying a linear range from 0.39 to 1.56 mu M with a limit of detection of 0.29 mu M. The selectivity of the proposed assay was assessed by performing two different negative control experiments; i) detection of testosterone with a randomized ssDNA sequence and ii) detection of two other steroids, i.e. deoxycholic acid and hydrocortisone with the TESS.1 aptamer. In parallel, complementary analytical techniques were employed to confirm the suggested mechanism: i) native nanoelectrospray ionization mass spectrometry (native nESI-MS) was used to determine the stoichiometry of the binding, and to characterize aptamer-target interactions; and, ii) isothermal titration calorimetry (ITC) was carried out to elucidate the dissociation constant (Kd) of the complex of testosterone and the TESS.1 aptamer. The combination of these techniques provided a complete understanding of the aptamer performance, the binding mechanism, affinity and selectivity. Furthermore, this important characterization carried out in parallel validates the real functionality of the aptamer (TESS.1) ensuring its use towards selective testosterone binding in further biosensors. This research will pave the way for the development of new aptamer-based assays coupled with ECL sensing for the detection of relevant small molecules.
      原文链接:
    • NSTL
    • Elsevier

    Single-particle analysis of tear fluid reveals abundant presence of tissue factor-exposing extracellular vesicles with strong coagulation activity

    Liu, HaishengYuan, WenliPang, QishengXue, Chengfeng...
    8页
    查看更多>>摘要：Extracellular vesicles (EVs) in easily accessible body fluids have emerged as a promising source for liquid biopsy. Although tear collection is fast, safe, and noninvasive, EVs of tear fluid are less studied and their involvement in physiological and pathological processes is largely unknown. The aim of present study was to analyze and characterize EVs in tear fluid at the single-particle level to reveal the population heterogeneity. A laboratory-built nano-flow cytometer (nFCM) was used to analyze the purity, size distribution, and particle concentration of EVs isolated from unstimulated tears (basal tears) upon double ultracentrifugation (17 min at 100,000 x g, 4 degrees C) via side scattering detection. The expression of CD9, CD63, CD81, CD47, CD45, CD24, and EpCAM was assessed via immunofluorescent detection. The EV concentration in tear fluid was measured to be 1.1 +/- 0.7 x 10(11) particles/mL, which is approximately 100-fold higher than that of plasma EVs. In particular, it was identified for the first time that tears have strong coagulant activity owing to the abundant presence of tissue factor (TF) on tear EVs. The concentration of TF-exposing EVs (4.4 +/- 3.1 x 10(10) particles/mL) was found to be approximately 100-fold higher than their counterparts in saliva (4.5 +/- 2.1 x 10(8) particles/mL). We postulate that TF-exposing vesicles in tears might play a role in host defense by promoting clot formation and thus reducing the risk of pathogen invasion. The coagulant activity of tears triggered by TF-exposing EVs could provide a new research perspective for ophthalmic research.
      原文链接:
    • NSTL
    • Elsevier

    Rapid electrochemical immunodetection of SARS-CoV-2 using a pseudo-typed vesicular stomatitis virus model

    Ashur, IdanAlter, JoelWerbner, MichalOgungbile, Abraham...
    8页
    查看更多>>摘要：The COVID-19 pandemic has highlighted the need for reliable and accurate diagnostic tools that provide quantitative results at the point of care. Real-time RT-PCR requires large laboratories, a skilled workforce, complex and costly equipment, and labor-intensive sample processing. Despite tremendous efforts, scaling up RTPCR tests is seemingly unattainable. To date, hundreds of millions of COVID-19 tests have been performed globally, but the demand for timely, accurate testing continues to outstrip supply. Antigen-based rapid diagnostic testing is emerging as an alternative to RT-PCR. However, the performance of these tests, namely their sensitivity, is still inadequate. To overcome the limitations of currently employed diagnostic tests, new tools that are both sensitive and scalable are urgently needed. We have developed a miniaturized electrochemical biosensor based on the integration of specific monoclonal antibodies with a biochip and a measurement platform, and applied it in the detection of Spike S1 protein, the binding protein of SARS-CoV-2. Using electrochemical impedance spectroscopy, quantitative detection of sub-nanomolar concentrations of Spike S1 was demonstrated, exhibiting a broad detection range. To demonstrate the applicability of the biosensor, we have further developed a SARS-CoV-2 pseudovirus based on Spike protein-pseudo-typed VSV platform. Specific detection of different concentrations of pseudovirus particles was feasible in <30 min. This new tool may largely contribute to the fight against COVID-19 by enabling intensive testing to be performed and alleviating most of the hurdles that plague current diagnostics.
      原文链接:
    • NSTL
    • Elsevier

    Aptamer-engineered gold nanorod driven an absorbance enhanced strategy for sensitive biomacromolecule profiling

    Mao, Jinpeng
    5页
    查看更多>>摘要：Gold nanorods (AuNRs)-based plasmonic biosensor offers new opportunity for quantification of biomacromolecules due to their high designability and low technical demands. However, existing methods for the optical detection of biomacromolecule require the targets to induce the aggregation or etching of AuNRs. This limits the range of targets that can be detected, because molecules at extremely low concentration are difficult to arouse aggregation or etching of AuNRs. Thus, it is still challenge to design a scheme for the biomacromolecules at extremely low concentration which can't arouse aggregation or etching of AuNRs based on their plasmonic property. This study proposes a universal absorbance enhanced strategy for biomacromolecule detection with aptamers engineered AuNRs. The biosensor assay (Apts/AuNRs) is designed through assembly of two aptamers on AuNRs to specified recognize the target biomacromolecules, forming closed-loop conformation based on the proximity-dependent ligation, producing absorbance enhancement in the plasmonic peak of AuNRs. It is interesting that the absorbance enhancement increases gradually with increasing protein concentration within a certain range, whereas no aggregation or etching of AuNRs was observed compared with the typical AuNRs based LSPR sensor. Taking advantage of the excellent near infrared light absorption of AuNRs, Apts/AuNRs could be utilized to detect red protein such as cytochrome C, which exhibited better performance than AuNPs based plasmonic sensor. On this basis, the selectivity detection of cytochrome C with the detection of limit down to picomole level was demonstrated. By changing the type of aptamers on AuNRs, the sensitive and credible method was also utilized for the analysis of telomerase activity in nerve cell lysate. Telomerase activity in 4 x 104 neuroblastoma cell was determined to be about 3.575 U/L, which was close to the result of ELISA kit. Good recovery was achieved using standard samples recovery. This study broadens the scope of AuNRs based plasmonic property and offer a simple, sensitive and selective strategy for biomacromolecules detection in complexed biofluid.
      原文链接:
    • NSTL
    • Elsevier

    Protein biosensor based on Schottky barrier nanowire field effect transistor

    Smolyarova, Tatyana E.Shanidze, Lev, VLukyanenko, Anna, VBaron, Filipp A....
    6页
    查看更多>>摘要：A top-down nanofabrication approach involving molecular beam epitaxy and electron beam lithography was used to obtain silicon nanowire-based back gate field-effect transistors with Schottky contacts on silicon-oninsulator (SOI) wafers. The resulting device is applied in biomolecular detection based on the changes in the drain-source current (I-DS). In this context, we have explained the physical mechanisms of charge carrier transport in the nanowire using energy band diagrams and numerical 2D simulations in TCAD. The results of the experiment and numerical modeling matched well and may be used to develop novel types of nanowire-based biosensors.
      原文链接:
    • NSTL
    • Elsevier

    Development of QDs-based nanosensors for heavy metal detection: A review on transducer principles and in-situ detection

    Wang, XinyiKong, LiubingZhou, ShuqiMa, Chiyu...
    13页
    查看更多>>摘要：Heavy metal pollution has severe threats to the ecological environment and human health. Thus, it is urgent to achieve the rapid, selective, sensitive and portable detection of heavy metal ions. To overcome the defects of traditional methods such as time-consuming, low sensitivity, high cost and complicated operation, QDs (Quantum dots)-based nanomaterials have been used in sensors to significantly improve the sensing performance. Due to their excellent physicochemical properties, high specific surface area, high adsorption and reactive capacity, nanomaterials could act as potential probes or offer enhanced sensitivity and create a promising nanosensors platform. In this review, the rapidly advancing types of QDs for heavy metal ions detection are first summarized. Modified with ligands, nanomaterials, or biomaterials, QDs are assembled on sensors by the interaction of electrostatic adsorption, chemical bonding, steric hindrance, and base-pairing. The stability of QDs-based nanosensors is improved by doping the elements to QDs, providing the reference substance, optimizing the assemble strategies and so on. Then, according to transducer principles, the two most typical sensor categories based on QDs: optical and electrochemical sensors are highlighted to be discussed. In the meanwhile, portable devices combining with QDs to adapt the practical detection in complex situations are summarized. The deficiencies and future challenges of QDs in toxicity, specificity, portability, multi-metal co-detection and degradation during the detection are also pointed out. In the end, the development trends of QDs-based nanosensors for heavy metal ions detection are discussed. This review presents an overall understanding, recent advances, current challenges and future outlook of QDs-based nanosensors for heavy metal detection.
      原文链接:
    • NSTL
    • Elsevier

    Cloud point extraction (CPE) combined with single particle -inductively coupled plasma-mass spectrometry (SP-ICP-MS) to analyze and characterize nano-silver sulfide in water environment

    Wei, Wen-JingYang, YuanLi, Xin-YuanHuang, Peng...
    9页
    查看更多>>摘要：Silver Nanoparticles (Ag-NPs), an emerging type of pollutant, might occur various physical and chemical transformations, which would affect its environmental fate, transformation and biological effects. Sulfurization is the most common conversion of Ag-NPs, accompanied by the formation of nano-silver sulfide (Ag2S-NPs). The method of Ag2S-NPs analysis and characterization is of great significance for assessing the environmental risks of Ag. In this study, cloud point extraction (CPE) and Single Particle-Inductively Coupled Plasma-Mass Spectrometry (SP-ICP-MS) were used in combination to establish a simple and reliable analysis method to quantify Ag2S-NPs in water, with the morphology unchanged. Non-Ag2S-NPs were dissociated into Ag+ firstly, and Ag2S-NPs and Ag+ were separated by CPE, followed by SP-ICP-MS analysis. The extraction rate based on particle number concentration was between (76.19 +/- 0.56) % to (106.35 +/- 0.00) % in environmental waters. Compared with the (76.96 +/- 2.18) nm Ag2S-NPs spiked, the particle size extracted increased slightly with (94.19 +/- 2.72) nm-(97.25 +/- 0.22) nm as the large-size Ag2S-NPs originally presented in waters, instead of agglomeration. This method could be generally applicable to the analysis of Ag2S-NPs in waters, and provide ideas for other metal sulfide nanoparticles (MS-NPs), which has certain significance.
      原文链接:
    • NSTL
    • Elsevier

    Recent advances in biosensor for DNA glycosylase activity detection

    Ouyang, YuzhenLiu, YifanDeng, YuanHe, Hailun...
    13页
    查看更多>>摘要：Base excision repair (BER) is vital for maintaining the integrity of the genome under oxidative damage. DNA glycosylase initiates the BER pathway recognizes and excises the mismatched substrate base leading to the apurinic/apyrimidinic site generation, and simultaneously breaks the single-strand DNA. As the aberrant activity of DNA glycosylase is associated with numerous diseases, including cancer, immunodeficiency, and atherosclerosis, the detection of DNA glycosylase is significant from bench to bedside. In this review, we summarized novel DNA strategies in the past five years for DNA glycosylase activity detection, which are classified into fluorescence, colorimetric, electrochemical strategies, etc. We also highlight the current limitations and look into the future of DNA glycosylase activity monitoring.
      原文链接:
    • NSTL
    • Elsevier

    A novel microfluidic RNA chip for direct, single-nucleotide specific, rapid and partially-degraded RNA detection

    Zhang, ShunChen, JiuyiLiu, DanHu, Bei...
    6页
    查看更多>>摘要：Direct RNA detection is critical for providing the RNA insights into gene expression profiling, noncoding RNAs, RNA-associated diseases and pathogens, without reverse transcription. However, classical RNA analysis usually requires RT-PCR, which can cause bias amplification and quantitation errors. To address this challenge, herein we report a microfluidic RNA chip (the microchip prototype) for direct RNA detection, which is primarily based on RNA extension and labeling with DNA polymerase. This detection strategy is of high specificity (discrimi-nating against single-nucleotide differences), rapidity, accuracy, nuclease resistance, and reusability. Further, we have successfully detected disease-associated RNAs in clinical samples, demonstrating its great potentials in biomedical research and clinical diagnosis.
      原文链接:
    • NSTL
    • Elsevier