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Talanta
Pergamon Press
Talanta

Pergamon Press

0039-9140

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    A regenerable and reducing false-positive fluorescent switch for detection of β-amyloid 1?42 oligomers

    Tan S.Li S.Qu Q.Li L....
    5页
    查看更多>>摘要：? 2022 Elsevier B.V.The conventional fluorescence analysis methods for disease identification are vulnerable to the restriction with false-positive. Here, a fluorescent switch with high efficiency and regeneration by the black phosphorus (BP) nanosheets-regulated was developed to overcome false-positive issue in the assay of β-amyloid1?42 oligomers (Aβ) process. The Aβ was rapidly recognized using the fluorescent emitter‐nitrogen-doped carbon nanodots (N-CDs) under the regulation of BP nanosheets, while the N-CDs alone cannot recognize Aβ without the introduction of BP. The fluorescence analysis methods exhibited a wide sensing range of 0.25–15.0 ng/mL and a low detection limit of 83 pg/mL for Aβ analysis, which was superior to the reported fluorescence analysis method. Further, BP nanosheets were recycled, demonstrating the fluorescent switch with highly efficient, stable, and regenerable. This provides a new idea for developing high-efficiency and high-precision fluorescence detection platform.
      原文链接:
    • NSTL
    • Elsevier

    Selection, truncation and fluorescence polarization based aptasensor for Weissella viridescens detection

    Ma P.Duan N.Xia Y.Wang Z....
    5页
    查看更多>>摘要：? 2022 Elsevier B.V.Weissella viridescens is a spoilage bacterium commonly found in low-temperature meat products. In this work, after fifteen rounds including three counter selection rounds of whole-cell systemic evolution of ligands by exponential enrichment (SELEX) in vitro, a novel aptamer L3 that can specifically recognize W. viridescens was obtained with a dissociation constant (Kd) value of 68.25 ± 5.32 nM. The sequence of aptamer L3 was optimized by truncation and a new aptamer sequence TL43 was obtained with a lower Kd value of 32.11 ± 3.01 nM. Finally, a simple and rapid fluorescence polarization (FP) platform was constructed to detect W. viridescens, in which FAM-labeled complementary sequence (FAM-cDNA) was employed to generate FP signal and streptavidin was used to amplify FP signal. In the presence of target bacteria, FP value decreased owning to the dissociation of FAM-cDNA from streptavidin/biotin-TL43/FAM-cDNA complex. Under optimal conditions, the concentration of W. viridescens and FP value displayed a good linear relationship with the detection range from 102 to 106 cfu/mL. Moreover, the designed detection system had a good recovery rate of 90.6%–107.7% in smoked ham samples compared with classical plate counting method, indicating the great potential of the selected and truncated aptamer in practical biosensing applications.
      原文链接:
    • NSTL
    • Elsevier

    Determination of Ag, Bi, Cd, Hg, Pb, Tl, and Zn by inductively coupled plasma mass spectrometry combined with vapor generation assisted by solution anode glow discharge – A preliminary study

    Greda K.Welna M.Pohl P.
    5页
    查看更多>>摘要：? 2022 The AuthorsA new technique of vapor generation assisted by a microplasma was proposed for an inductively coupled plasma mass spectrometry (ICP MS). It was found that, by replacing a traditional pneumatic nebulizer with a microplasma (solution anode glow discharge, SAGD), analytical signals of Ag, Bi, Cd, Hg, Pb, Tl, and Zn were improved 8, 4, 13, 13, 9, 10, and 7 times, respectively. The main factor contributing to boosted analytical signal intensities was the higher analyte flux produced by the novel microplasma system. The measurement precision in SAGD-ICP MS was comparable to that achievable for ICP MS (with pneumatic nebulization), and it did not exceed 2%. The detection limits of Ag, Bi, Cd, Hg, Pb, Tl, and Zn in SAGD-ICP MS were 5, 2, 6, 5, 4, 10, and 20 ng L?1, respectively. The analytical performance of this method may be further improved if the observed memory effects could be minimized. To validate the trueness of the novel method, certified reference materials of lobster hepatopancreas (TORT-2), cormorant tissue (MODAS-4), and wastewater (ERM CA-713) were analyzed to determine traces of Cd, Hg, and Pb. Recoveries of certified values for these analytes were ranged from 91 to 111%, which indicated that the studied microplasma system in combination with ICP MS can be successfully used for very sensitive determinations of selected hazardous elements in environmental samples.
      原文链接:
    • NSTL

    A rapid multiplex nucleic acid detection system of airborne fungi by an integrated DNA release device and microfluidic chip

    Sui G.Lu H.Zhu J.Zhang T....
    5页
    查看更多>>摘要：? 2022Occupational health problems, such as asthma, in specific work environments arise from the presence of airborne fungi. Rapid detection of pathogenic airborne fungi is therefore important to reduce or avoid any adverse effects on staff health. Herein, we established a new integrated rapid Lyticase-Motor-Chemical reagent nucleic acid releasing (LMC) method for the release of fungal DNA. Aspergillus fumigatus, Aspergillus flavus, and Cryptococcus neoformans were chosen to evaluate the LMC method. The results of Loop-Mediated Isothermal Amplification (LAMP) analyses showed that this method could release the nucleic acid of 4 × 104 fungal spores, equaling to 400 copies per microliter. This rapid multiplex nucleic acid detection system of airborne fungi included an integrated DNA release device and a portable microfluidic chip. The integrated DNA release device combined mechanical lysing and biochemical reagent treatment to automate DNA release. The microfluidic chip was capable of multiplex nucleic acid detection. The detection limit of this system was 4 × 104 spores per test, meeting the requirement of early warnings. The whole analysis from the sample input to readout could be completed within 90 min, including 30 min for fungal DNA release and 45 min for LAMP analysis. The integrated DNA release device and microfluidic chip were portable, showing tremendous potential in point-of-care tests of airborne fungi.
      原文链接:
    • NSTL
    • Elsevier

    Monitoring multiple quality attributes of a complex Fc-fusion protein during cell culture production processes by mD-LC-MS peptide mapping

    Camperi J.Stella C.Dahotre S.Guillarme D....
    5页
    查看更多>>摘要：? 2022Fc-fusion proteins represent a successful class of biopharmaceutical products. They are considered highly heterogeneous products due to the common degradation of amino acids that occurs during their production in upstream and downstream processes (e.g., oxidation and deamidation) and, above all, their complex glycosylation profile. Multi-dimensional liquid chromatography-mass spectrometry (mD-LC-MS) has recently gained much interest for process analytical technology, enabling the integration of this analytical technology in production and purification environments. In this study, an online mD-LC-MS/MS peptide mapping method was developed for monitoring multiple quality attributes, including the N-glycosylation state of a complex Fc-fusion protein, which is made by combining two heavily glycosylated cytokines with an Fc domain. This fully automated workflow includes sample purification, reduction, digestion, peptide mapping, and subsequent mass spectrometric analysis. Two immobilized enzyme cartridges based on trypsin and Lys-C protease were employed to generate a detailed glycosylation mapping, as trypsin allowed the identification of only one of four glycosylation sites, while Lys-C was more informative for two other sites. Site-specific glycosylation information such as antennarity, sialyation, and core fucosylation state was also determined. In addition to glycans, other post-translational modifications could be monitored simultaneously during the cell culture production processes by the mD-LC-MS/MS approach. In summary, the generated data demonstrate the applicability of mD-LC-MS for the monitoring and trending of multiple attributes for complex antibody formats over production processes in an automated and fast manner, compared to the complex and time-consuming traditional offline assays.
      原文链接:
    • NSTL
    • Elsevier

    Fe single atoms anchored on fluorine-doped ultrathin carbon nanosheets for sensitive colorimetric detection of p-phenylenediamine

    Chen X.Feng M.Xie X.Zhang Y....
    5页
    查看更多>>摘要：? 2022 Elsevier B.V.Single-atom catalysts have attracted enormous research interest in the field of catalysis owing to their remarkable catalytic activity, excellent stability and outstanding atom utilization. Herein, a new single atom based on single Fe atoms on fluorine-doped (Fe–SAs@FNC) ultrathin carbon nanosheets was successfully synthesized by a polymer-assisted heating method. Experimental evidence showed that the resultant Fe–SAs@FNC with Fe–N4 sites exhibits superior peroxidase-like activity, which oxidizes the colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to produce a blue product in the presence of hydrogen peroxide (H2O2). Based on this, an ultrasensitive and highly selective colorimetric detection method for p-phenylenediamine (PPD) in hair dyes and PPD in hair after dyeing was established, which had a wide linear range (0.2–50 μM) and low detection limit (0.07 μM). This method shows satisfactory sensitivity and selectivity.
      原文链接:
    • NSTL
    • Elsevier

    Discrimination of tumor cell type based on cytometric detection of dielectric properties

    Jiang L.Xiang N.Ni Z.Tang D....
    5页
    查看更多>>摘要：? 2022 Elsevier B.V.In this paper, a microfluidic impedance cytometer (MIC) was employed to analyze the dielectric properties of human white blood cells (WBCs) and four tumor cell lines and realize the label-free identification of cell types. The impedance of cells was detected using an asymmetric serpentine microchannel based MIC under four different frequencies simultaneously. The asymmetric serpentine microchannel achieved the elasto-inertial focusing of cells into a single train, ensuring accurate impedance detection of cells. Various dielectric parameters (cell diameters, impedance amplitude |Z|, impedance phase shift ΦZ, and electric opacities |Z|HF/|Z|LF, ΦZHF/ΦZLF, Re(ZHF)/Re(ZLF), and Im(ZHF)/Im(ZLF)) were defined and used to analyze the dielectric properties of cells. The obtained dielectric parameters were used to train machine learning classification models for identifying cell types. Using all parameters proposed in this paper (cell diameter, opacity |Z|HF/|Z|LF, ΦZHF/ΦZLF, Re(ZHF)/Re(ZLF), and Im(ZHF)/Im(ZLF)) to train the classification model, the true positive rate (TPR) for the identification of WBCs, A549, MCF7, H226, and H460 cells were 99.6%, 96.2%, 99.1%, 97.6%, and 97.2%, respectively. Results showed that our MIC provided a promising method for label-free discrimination of circulating tumor cells in multiple primary cancers.
      原文链接:
    • NSTL
    • Elsevier

    Smart fluorescence aptasensor using nanofiber functionalized with carbon quantum dot for specific detection of pathogenic bacteria in the wound

    Pebdeni A.B.Hosseini M.Barkhordari A.
    5页
    查看更多>>摘要：? 2022 Elsevier B.V.We developed for the first time a novel and smart nanofiber (NF) network with the electrospinning method to create an amplified fluorescent biosensing platform for the detection of Staphylococcus aureus (S. aureus) bacteria in wound. The sensing platform is constructed based on surface modification of NFs by carbon quantum dots (CQDs) on the NF membrane surface, leading to large fluorescence signal amplification. CQDs synthesis was done from orto-phenylenediamine (OPD) with yellow emission fluorescence. Incorporation of CQDs leads to the uniform fluorescence of modified NFs. The proposed biosensing platform can also be applied to detect S. aureus bacteria with high sensitivity and selectivity via a specific aptamer. The linear sensing range for different S. aureus concentration from 10 to 108 CFU/mL and the detection limit of 10 CFU/mL was attained. For the first time these scaffolds were designed for the detection of specific pathogenic bacteria in wound using fluorescence signal of NFs, which can be seen by the naked eye under UV lamp. Enhancing in the fluorescence intensity after putting the modified NFs on skin wounds of mice for 2 h showed the successful application of this novel aptasensor.
      原文链接:
    • NSTL
    • Elsevier

    Assisting dementia diagnosis through the electrochemical immunosensing of glial fibrillary acidic protein

    Ozcelikay G.Ozkan S.A.Gamella M.Pingarron J.M....
    5页
    查看更多>>摘要：? 2022Glial fibrillary acidic protein (GFAP) is a member of the intermediate filament family of proteins with increased levels in serum and cerebrospinal fluid of patients with Alzheimer disease (AD) and other neurodegenerative diseases (NDs), such as vascular dementia (VD). This work describes the first magnetic microbeads (MBs)-based electrochemical immunoplatform for GFAP determination. The platform design comprises a sandwich immunoassay implemented on the MBs surface and amperometric transduction at single-use screen-printed carbon electrodes (SPCEs). Micro-sized carboxylic acid magnetic particles (COOH-MBs) were modified with a specific capture antibody (CAb) to selectively link the target protein, which was sandwiched with a biotinylated detector antibody (btn-DAb) further conjugated with a streptavidin-peroxidase (Strep-HRP) conjugate. Amperometric transduction was performed at SPCEs upon capturing the magnetic bioconjugates on their surface and through the hydrogen peroxide/hydroquinone (H2O2/HQ) system. The immunoplatform achieved a limit of detection of 67 pg mL?1 for the amperometric detection of standards and selectivity compatible with clinical applicability to assist in minimally invasive NDs diagnosis and prognosis. The MBs-based immunoplatform was applied with good results to determine the endogenous content of GFAP in protein brain extracts without matrix effect and using just 6.25 ng of sample per determination. Furthermore, the developed methodology was capable of differentiating between healthy subjects and patients diagnosed with VD and AD in only 2 h, providing accurate results in line with those obtained by an ELISA kit that used the same immunoreagents.
      原文链接:
    • NSTL
    • Elsevier

    Method development for PPB culture screening, pigment analysis with UPLC-UV-HRMS vs. spectrophotometric methods, and spectral decomposition-based analysis

    Hulsen T.Yong K.W.L.Grassino M.Batstone D.J....
    5页
    查看更多>>摘要：? 2022 Elsevier B.V.PPB carotenoids are usually measured through spectrophotometric analysis, measuring total carotenoids (TCs) which has low accuracy and cannot identify individual carotenoids or isomers. Here, we developed an ultra-performance liquid chromatography method with ultraviolet and high-resolution mass spectrometry detection (UPLC-UV-HRMS) to quantify neurosporene, lycopene, and bacteriochlorophyll a contents in PPB cultures. The method exhibited satisfactory recoveries for individual pigments (between 82.1% and 99.5%) and was applied to a range of mixed PPB cultures. The use of a C30 column also enabled the detection of three different isomers of lycopene. In addition, a method for anaerobic photoheterotrophic PPB cultivation to acquire live-cell spectrophotometric information was developed and tested by modifying a standard microbial culture microplate system. A rapid, and relatively low effort principal component analysis (PCA) based decomposition of the whole-cell spectra for pigment analysis in the microplates was also developed. Analysing whole-cell spectra via PCA allowed more accurate prediction of individual pigments compared to absorption methods, and can be done non-destructively, during live-cell growth, but requires calibration for new media and microbial matrices.
      原文链接:
    • NSTL
    • Elsevier