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Pergamon Press
Talanta

Pergamon Press

0039-9140

Talanta/Journal TalantaSCIISTPEIAHCI
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    A label-free cyclic amplification strategy for microRNA detection by coupling graphene oxide-controlled adsorption with superlong poly (thymine)-hosted fluorescent copper nanoparticles

    Xu, FengzhouQiao, ZhenzhenLuo, LanHe, Xiaoxiao...
    8页
    查看更多>>摘要：Herein, based on a terminal deoxynucleotidyl transferase (TdT)-mediated superlong poly-T-templated-copper nanoparticles (poly T-CuNPs) strategy, a simple, universal and label-free fluorescent biosensor for the detection of miRNA was constructed by employing graphene oxide (GO) and DNase I. In this strategy, GO and DNase I were used as a switch and amplifier of the signal generation pathway, respectively, and the fluorescence of poly T-CuNPs was used as the signal output. In the presence of target miRNA, the DNA dissociated from the GO surface by forming a miRNA/DNA duplex and was degraded by DNase I. The short oligos with 3'-OH, the product of DNase I degradation, could be recognized by the TdT and added to a long poly-T tail. Finally, the fluorescence signal was output through the synthesis of poly T-CuNPs. As a proof of concept, let-7a was analyzed. The method showed good sensitivity and selectivity with a linear response in the 50 pM-10,000 pM let-7a concentration range and a 30 pM limit of detection (LOD = 30 pM, R-2 = 0.9954, the relative standard deviation were 2.79%-5.30%). It was also successfully applied to the determination of miRNA in spiked human serum samples. It showed good linearity in the range of 500-10000 pM (R-2 = 0.9969, the relative standard deviation were 1.61%-3.85%). Moreover, both the adsorption of GO and the degradation of DNase I are DNA sequence-independent; thus, this method can be applied to the detection of any miRNA simply by changing the assisted-DNA sequence.
      原文链接:
    • NSTL
    • Elsevier

    Ginsenoside Rg3 determination using an electro-synthesized molecularly imprinted polymer on MWCNT-Ti3C2Tx nanocomposite modified electrode

    Hu, JinchunZhang, ZhenguoZhang, CongcongZhang, Jiancheng...
    8页
    查看更多>>摘要：Rare ginsenoside Rg3 is a main active ingredient in ginseng, which is more easily absorbed by human body and plays its role. Determination of Rg3 in edible and medicinal samples is a key factor for quality evaluation and effective monitoring of adulteration. In this study, an electrochemical sensor was developed based on molecularly imprinted polymer (MIP) and nanomaterial amplification. MIP was achieved by electro-polymerization with Rg3 as the template molecule and the functional monomer was o-phenylenediamine. Multi-walled carbon nanotubes (MWCNT) and titanium carbide (Ti3C2Tx) nanocomposites formed an excellent porous structure, which exhibited the advantages of increasing the specific surface area and electrical conductivity. The prepared sensor presented a great linear relation of Rg3 in the range of 10-2000 mu g mL(-1) with a limit of detection (LOD) of 0.34 mu g mL(-1). Importantly, the sensor was successfully utilized to detect ginsenoside Rg3 in different real samples.
      原文链接:
    • NSTL
    • Elsevier

    beta-1,4-Galactosyltransferase-V colorectal cancer biomarker immunosensor with label-free electrochemical detection

    Echeverri, DaniloOrozco, Jahir
    11页
    查看更多>>摘要：beta-1,4-Galactosyltransferase-V (beta-1,4-GalT-V) is a membrane-bound glycoprotein with glycosyltransferase enzyme activity that synthesizes lactosylceramide and glycosylates high-branched N-glycans in the Golgi apparatus. Colorectal cancer (CRC) tumor cells have shown to overexpress these biomolecules concerning normal cells, releasing them into the body fluids. Thus, their detection has been suggested as a diagnosis/prognosis CRC biomarker. We report the first electrochemical immunosensor for the detection of such a novel beta-1,4-GalT-V CRC biomarker. The label-free electrochemical immunosensor covalently coupled an anti-beta-1,4-GalT-V antibody at a mixed self-assembled monolayer-coated screen-printed gold electrode (SPAuE) surface. This functionalized platform captured the beta-1,4-GalT-V glycoprotein from human serum samples with high specificity, which response monitored by electrochemical impedance spectroscopy (EIS) was protein concentration-dependent. The resultant electrochemical immunosensor showed a linear dynamic range from 5 to 150 pM, with a sensitivity of 14 Omega pM(-1) and a limit of detection of 7 pM, of clinical relevance. This outstanding performance makes it great potential for including it in a biomarker signature for the early diagnosis/prognosis of CRC.
      原文链接:
    • NSTL
    • Elsevier

    Monitoring autoimmune diseases by bioelectrochemical detection of autoantibodies. Application to the determination of anti-myelin basic protein autoantibodies in serum of multiple sclerosis patients

    Guerrero, S.Sanchez-Tirado, E.Agui, L.Gonzalez-Cortes, A....
    6页
    查看更多>>摘要：This work reports an amperometric bioplatform for the determination of anti-myelin basic protein autoantibodies (anti-MBP), a relevant biomarker for multiple sclerosis (MS) autoimmune disease. The developed configuration involves the use of carboxylated magnetic microparticles (cMBs) where the protein for specific capture of the target autoantibodies was covalently attached. The immobilized anti-MBP were further conjugated with a secondary antibody labelled with horseradish peroxidase (HRP-anti-hIgG) and amperometric transduction was performed by adding hydrogen peroxide and using hydroquinone (HQ) as redox mediator. The cathodic current resulting from the reduction of the corresponding quinone was directly proportional to the logarithmic concentration of the target autoantibodies. The analytical performance of the developed method for the determination of anti-MBP is competitive in terms of sensitivity and range of linearity with that claimed for the only biosensor reported so far in the literature, as well as with commercially available ELISA kits showing a remarkably shorter assay time. The bioplatform was applied to the analysis of serum samples of healthy individuals and patients diagnosed with MS providing results in agreement with the ELISA methodology.
      原文链接:
    • NSTL
    • Elsevier

    Indiscriminate SARS-CoV-2 multivariant detection using magnetic nanoparticle-based electrochemical immunosensing

    Arda, BilginGoksel, TuncayTurhan, KutsalTimur, Suna...
    10页
    查看更多>>摘要：The increasing mutation frequency of the SARS-CoV-2 virus and the emergence of successive variants have made correct diagnosis hard to perform. Developing efficient and accurate methods to diagnose infected patients is crucial to effectively mitigate the pandemic. Here, we developed an electrochemical immunosensor based on SARS-CoV-2 antibody cocktail-conjugated magnetic nanoparticles for the sensitive and accurate detection of the SARS-CoV-2 virus and its variants in nasopharyngeal swabs. The application of the antibody cocktail was compared with commercially available anti-SARS-CoV-2 S1 (anti-S1) and anti-S2 monoclonal antibodies. After optimization and calibration, the limit of detection (LOD) determination demonstrated a LOD = 0.53-0.75 ng/ mL for the antibody cocktail-based sensor compared with 0.93 ng/mL and 0.99 ng/mL for the platforms using anti-S1 and anti-S2, respectively. The platforms were tested with human nasopharyngeal swab samples pre diagnosed with RT-PCR (10 negatives and 40 positive samples). The positive samples include the original, alpha, beta, and delta variants (n = 10, for each). The polyclonal antibody cocktail performed better than commercial anti-S1 and anti-S2 antibodies for all samples reaching 100% overall sensitivity, specificity, and accuracy. It also showed a wide range of variants detection compared to monoclonal antibody-based platforms. The present work proposes a versatile electrochemical biosensor for the indiscriminate detection of the different variants of SARS-CoV-2 using a polyclonal antibody cocktail. Such diagnostic tools allowing the detection of variants can be of great efficiency and economic value in the fight against the ever-changing SARS-CoV-2 virus.
      原文链接:
    • NSTL
    • Elsevier

    A simple method for glass analysis using total reflection X-ray fluorescence spectrometry

    Costa, Cassiano L. S.Prais, Claudia T.Nascentes, Clesia C.
    7页
    查看更多>>摘要：In this work, a simple and cost-effective method was developed for Na, Mg, Al, K, Ca, Ti, V, Cr, Mn, Ni, Cu, Zn, Rb, Sr, Ba and Pb determination in glass samples employing suspension sampling and total reflection X-ray fluorescence (TXRF). The experimental conditions were optimized using multivariate approach being the optimum conditions located by Derringer's desirability function. Proposed method was validated in accordance with the National Institute of Metrology, Quality and Technology (Inmetro, Brazil). Limit of detection (LD) and limit of quantification (LQ) were adequate for determination of trace elements in glass. The evaluation of the accuracy and precision was realized by analysis of standard reference materials of glass (NIST 612). For the majority of the elements, good agreement was achieved between the certified value and the value obtained in the NIST 612. The relative standard deviation (RSD%) was achieved between 3.6 and 10.3%. Moreover, no significant differences were observed between the proposed method compared to the ICP-MS. After the validation step, the method was applied to 31 glass samples and with aid of an exploratory principal component analysis (PCA), a perfect discrimination of the glass from originally manufactured smartphones was obtained. In addition, soda-lime glass could be reasonably distinguished from smartphone screens. The developed method is fast, consumes low amounts of reagents and allows the determination of many analytes simultaneously. Additionally, the method does not require calibration curves. Therefore, TXRF proved to be attractive and useful for routine analysis of glass.
      原文链接:
    • NSTL
    • Elsevier

    Target-responsive DNA hydrogel with microfluidic chip smart readout for quantitative point-of-care testing of creatine kinase MB

    Zhao, XudongChen, MengmengWang, YuPeng, Yuan...
    7页
    查看更多>>摘要：Swift and effective diagnosis of acute myocardial infarction (AMI) is critical to patient survival due to its serious life-threatening effects and increasing incidence. Creatine kinase MB (CK-MB) is one of the markers of AMI. In this work, we enabled a portable visual quantitative assay of CK-MB by incorporating target-responsive DNA hydrogel with a microfluidic chip. The CK-MB aptamer and the complementary short DNA strand were grafted onto the polyacrylamide strand separately and formed the hydrogel by base-paired linkage. Upon introduction of CK-MB, the aptamer bound to CK-MB. This led to hydrogel dissociation and subsequent release of pre-trapped gold nanoparticles (AuNPs), which is proportional to the concentration of CK-MB. To achieve portable on-site detection, we further combined the hydrogel with a microfluidic chip and utilized the color change caused by the released AuNPs to take picture and analyze the average gray value. Then, as low as 0.027 nM CK-MB could be detected by cell phone. With good portability, visualization, and simple sample handling, this method has great potential for quantitative point-of-care testing (POCT) of targets in resource-constrained settings.
      原文链接:
    • NSTL
    • Elsevier

    Detection of SARS-CoV-2 virus via dynamic light scattering using antibody-gold nanoparticle bioconjugates against viral spike protein

    da Silva, Patricia Bentoda Silva, Jaqueline RodriguesRodrigues, Mosar CorreaVieira, Julia Augusto...
    7页
    查看更多>>摘要：Mass testing for the diagnosis of COVID-19 has been hampered in many countries owing to the high cost of genetic material detection. This study reports on a low-cost immunoassay for detecting SARS-CoV-2 within 30 min using dynamic light scattering (DLS). The immunosensor comprises 50-nm gold nanoparticles (AuNPs) functionalized with antibodies against SARS-CoV-2 spike glycoprotein, whose bioconjugation was confirmed using transmission electron microscopy (TEM), UV-Vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), and surface-enhanced Raman scattering spectroscopy (SERS). The specific binding of the bioconjugates to the spike protein led to an increase in bioconjugate size, with a limit of detection (LOD) 5.29 x 10(3) TCID50/mL (Tissue Culture Infectious Dose). The immunosensor was also proven to be selective upon interaction with influenza viruses once no increase in size was observed after DLS measurement. The strategy proposed here aimed to use antibodies conjugated to AuNPs as a generic platform that can be extended to other detection principles, enabling technologies for low-cost mass testing for COVID-19.
      原文链接:
    • NSTL
    • Elsevier

    Using machine learning and an electronic tongue for discriminating saliva samples from oral cavity cancer patients and healthy individuals

    Braz, Daniel C.Neto, Mario PopolinShimizu, Flavio M.Sa, Acelino C....
    8页
    查看更多>>摘要：The diagnosis of cancer and other diseases using data from non-specific sensors - such as the electronic tongues (e-tongues) -is challenging owing to the lack of selectivity, in addition to the variability of biological samples. In this study, we demonstrate that impedance data obtained with an e-tongue in saliva samples can be used to diagnose cancer in the mouth. Data taken with a single-response microfluidic e-tongue applied to the saliva of 27 individuals were treated with multidimensional projection techniques and non-supervised and supervised machine learning algorithms. The distinction between healthy individuals and patients with cancer on the floor of mouth or oral cavity could only be made with supervised learning. Accuracy above 80% was obtained for the binary classification (YES or NO for cancer) using a Support Vector Machine (SVM) with radial basis function kernel and Random Forest. In the classification considering the type of cancer, the accuracy dropped to ca. 70%. The accuracy tended to increase when clinical information such as alcohol consumption was used in conjunction with the e-tongue data. With the random forest algorithm, the rules to explain the diagnosis could be identified using the concept of Multidimensional Calibration Space. Since the training of the machine learning algorithms is believed to be more efficient when the data of a larger number of patients are employed, the approach presented here is promising for computer-assisted diagnosis.
      原文链接:
    • NSTL
    • Elsevier

    Highly sensitive multiplex detection of foodborne pathogens using a SERS immunosensor combined with novel covalent organic frameworks based biologic interference-free Raman tags

    Yang, YanLi, GuoliangWang, PanxueFan, Lihua...
    10页
    查看更多>>摘要：Rapid and reliable multiplex detection of foodborne pathogens is in great demand for ensuring food safety and preventing foodborne diseases. In this study, we developed a highly sensitive SERS immunosensor for the simultaneous detection of multiple foodborne pathogens. Novel biologic interference-free Raman tags synthesized by using the covalent organic frameworks (COF) TBDP as nanocontainer to load biologic interference-free Raman reporters and specific antibodies for interested targets were used to convert and amplify signals of foodborne pathogens. In addition, lectin functionalized magnetic nanoparticles (MNPs@Con A) which could efficiently bind to the carbohydrate constituents on the surface of pathogens were prepared to capture and isolate multiple pathogens simultaneously. The recognition of the target foodborne pathogen impels the generation of sandwich-like composites of MNPs@Con A/pathogen/TBDP@Raman tags, and these composites could be quickly separated from the sample matrix with the assistance of an external magnet. Besides, a mass of Raman reporters was released by eluting the collected MNPs@Con A/pathogen/TBDP@Raman tags composites. Combined with a portable Raman system, characteristic Raman signals (2271 and 2113 cm-1) of the occupied reporters located at the biologic interference-free region were observed and used for the simultaneous detection of two different foodborne pathogenic strains. And an equal limit of detection of 101 CFU/mL was achieved for each strain. This strategy provides new insight into the application of SERS in the detection of pathogenic bacteria.
      原文链接:
    • NSTL
    • Elsevier