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Ultrasensitive immunoassay

Ruiguo Wang, Wei Zhang, Peilong Wang, Xiaoou Su
An ultrasensitive paper based lateral flow assay is described for rapid and simultaneous fluorometric detection of several β-agonists including clenbuterol and its chemical analogues (mabuterol, brombuterol, cimaterol, cimbuterol, bromchlorbuterol and banbuterol). A nonspecific monoclonal antibody (mAb) against clenbuterol and its analogues was prepared and employed in a competitive immunoassay where mAb conjugated to fluorescent nanoparticles and free β-agonists compete for the binding sites. This enables rapid screening for the 7 β-agonists in a single run that takes about 8 min...
2018: Mikrochimica Acta
Andrew Geoffrey Bourne Thompson, Connie Luk, Amanda J Heslegrave, Henrik Zetterberg, Simon H Mead, John Collinge, Graham S Jackson
OBJECTIVES: A blood-based biomarker of neuronal damage in sporadic Creutzfeldt-Jakob disease (sCJD) will be extremely valuable for both clinical practice and research aiming to develop effective therapies. METHODS: We used an ultrasensitive immunoassay to measure two candidate biomarkers, tau and neurofilament light (NfL), in serum from patients with sCJD and healthy controls. We tested longitudinal sample sets from six patients to investigate changes over time, and examined correlations with rate of disease progression and associations with known phenotype modifiers...
February 27, 2018: Journal of Neurology, Neurosurgery, and Psychiatry
Viviana A Carcamo Yañez, Jens C Göpfert, Markus Otto, Hayrettin Tumani, Andreas Peter, Thomas O Joos
Procalcitonin (PCT) is well established as a highly specific biomarker for the detection of bacterial infections and sepsis. However, the currently available diagnostic tests are not able to detect very low or very early increases of PCT or even baseline levels in healthy individuals or patients with non-bacterial infections. In order to be able to detect these very low concentrations of PCT, a sandwich immunoassay was developed using high sensitivity Single Molecule Array technology (Simoa). The assay was thoroughly validated and applied to analyze human cerebrospinal fluid (CSF) and serum samples from patients with bacterial or viral meningitis as well as CSF, serum, and K2 EDTA plasma from healthy control subjects...
November 16, 2017: High Throughput
María L Scala-Benuzzi, Julio Raba, Galo J A A Soler-Illia, Rudolf J Schneider, Germán A Messina
We report a novel and innovative electrochemical paper-based immunocapture assay (EPIA) to address the need for ultrasensitive detection of emerging pollutants without regulatory status and whose effects on environment and human health are not completely yet understood. In particular, we present the application of this system towards highly sensitive detection of the emerging pollutant ethinyl estradiol (EE2). The EPIA approach is based on the use of paper microzones modified with silica nanoparticles (SNs) and anti-EE2 specific antibodies for capture and pre-concentration of EE2 from river water samples...
February 23, 2018: Analytical Chemistry
Mingsha Jie, Songcheng Yu, Fei Yu, Lie Liu, Leiliang He, Yanqiang Li, Hongquan Zhang, Lingbo Qu, Peter de B Harrington, Yongjun Wu
BACKGROUND: In this work, a novel highly sensitive magnetic enzyme chemiluminescence immunoassay (MECLIA) was developed to detect fumonisin B1 (FB1 ) in cereal samples. The gold-coated magnetic nanoparticles (Fe3 O4 @Au, GoldMag) were used as solid phase carrier to develop a competitive CLIA for detecting FB1 , in which FB1 in samples would compete with FB1 -OVA coated on the surface of Fe3 O4 @Au nanoparticles in binding with FB1 antibodies. Successively, horseradish peroxidase labeled goat anti-rabbit IgG (HRP-IgG) was conjugated with FB1 antibodies on the microplate...
February 12, 2018: Journal of the Science of Food and Agriculture
Di Zhang, Li Huang, Bing Liu, Haibin Ni, Liangdong Sun, Enben Su, Hongyuan Chen, Zhongze Gu, Xiangwei Zhao
Rapid and sensitive quantification of multiplex proteins in a wide concentration range is challenging in high throughput analysis. Herein, we proposed a lateral flow assay (LFA) based on core-shell surface enhanced Raman scattering (SERS) nanotags for multiplex and quantitative detection of cardiac biomarkers for the early diagnosis of acute myocardial infarction (AMI). In practice, Raman dyes (RDs) were embedded into the interior-gap of silver core and gold shell nanoparticles (NPs) to form SERS nanotags as labels instead of gold colloids and three test lines were employed in the strip for the detection of three cardiac biomarkers, Myo, cTnI, and CK-MB, respectively...
February 1, 2018: Biosensors & Bioelectronics
Ying Zhou, Yanqing Yu, Yaqin Chai, Ruo Yuan
Herein, a novel electrochemiluminescence resonance energy transfer (ERET) strategy between in situ electrogenerated silver nanoclusters (AgNCs) as the donor and Ru(bpy)2(5-NH2-1,10-phen)Cl2 (Ru(II)) as the acceptor was reported, which was applied for the construction of a ultrasensitive immunosensor for the determination of apolipoprotein-A1 (Apo-A1). Notably, the Ag NCs were in suit electro-reducted on glassy carbon electrode (GCE) based on a simple, fast and controllable electrochemical technique, which acted as not only biocompatible ECL emitters, but also protein immobilization platform via Ag-N or Ag-S bond...
May 1, 2018: Talanta
Zhen Cao, Yu Zhu, Yang Liu, Shurong Dong, Xin Chen, Fan Bai, Shengxin Song, Junxue Fu
A nanoscale insulator-based dielectrophoresis (iDEP) technique is developed for rapid enrichment of proteins and highly sensitive immunoassays. Dense arrays of nanorods (NDs) by oblique angle deposition create a super high electric field gradient of 2.6 × 1024 V2 m-3 and the concomitant strong dielectrophoresis force successfully traps small proteins at a bias as low as 5 V. 1800-fold enrichment of bovine serum albumin protein at a remarkable rate of up to 180-fold s-1 is achieved using oxide coated Ag nanorod arrays with pre-patterned sawtooth electrodes...
January 26, 2018: Small
Tian Wen, Chao Huang, Yi Zhang, Xiaoyan Zeng, Wendong Liu, Zhenbang Jiao, Xiling Guo, Yongjun Jiao
A rapid and sensitive two-step time-resolved fluorescence immunoassay (TRFIA) was developed for the detection of Shiga toxin 2 (Stx2) and its variants in Shiga toxin-producing Escherichia coli (STEC) strains. In sandwich mode, a monoclonal antibody against Stx2 was coated on a microtiter plate as a capture antibody. A tracer antibody against Stx2 labeled with europium(III) (Eu3+ ) chelate was then used as a detector, followed by fluorescence measurements using time-resolved fluorescence. The sensitivity of Stx2 detection was 0...
January 19, 2018: Luminescence: the Journal of Biological and Chemical Luminescence
Anita Talan, Annu Mishra, Sergei A Eremin, Jagriti Narang, Ashok Kumar, Sonu Gandhi
Chlorpyrifos (chl) is an organophosphate pesticide extensively used in agriculture and highly toxic for human health. Fluorine doped tin-oxide (FTO) based electrochemical nanosensor was developed for chlorpyrifos detection with gold nanoparticles (AuNPs) and anti-chlorpyrifos antibodies (chl-Ab). AuNPs provides high electrical conductivity and specific resistivity, thus increases the sensitivity of immunoassay. High electrical conductivity of AuNPs reveals that it promotes the redox reaction for better cyclic voltammetry...
January 9, 2018: Biosensors & Bioelectronics
Sitian Tang, Huawei Shen, Yixiong Hao, Zhenglan Huang, Yiyi Tao, Yang Peng, Yongcan Guo, Guoming Xie, Wenli Feng
Circulating tumor cells (CTCs), as the cellular origin of metastasis, are cancer cells that break away from a primary tumor and circulate in the peripheral blood. And they provide a wealth of information about tumor phenotype. Here, this work reported a novel ultrasensitive immunoassay protocol for the detection of CTCs by using Pt@Ag nanoflowers (Pt@AgNFs) and AuNPs/Acetylene black (AuNPs/AB) nanomaterial. In the established approach, AuNPs/AB nanomaterial was used as substrate material to increase the specific surface area and enhance the conductivity of the gold electrode...
January 4, 2018: Biosensors & Bioelectronics
Peng Liu, Xueen Fang, Hongmei Cao, Mingli Gu, Jilie Kong, Anmei Deng
With the development of proteomics and the continuous discovery of biomarkers of trace proteins, it is important to accurately quantify low abundance protein, especially in urine for clinical diagnostics. In this paper, we reported a novel nano-biotinylated liposome-based immuno-loop-mediated isothermal amplification (LI-LAMP) for the ultrasensitive detection of REG1A (a biomarker for pancreatic ductal adenocarcinoma (PDAC) in urine) with high specificity. The detection range was 1µg/mL to 1fg/mL, with a detection limit of 1fg/mL, and no cross-reactivity was observed to occur in this assay...
March 1, 2018: Talanta
Lu Yang, Wenfang Deng, Chang Cheng, Yueming Tan, Qingji Xie, Shouzhuo Yao
Herein, carbon dots (CDs)-encapsulated breakable organosilica nanocapsules (BONs) were facilely prepared and used as advanced fluorescent labels for ultrasensitive detection of Staphylococcus Aureus (S. Aureus). CDs were entrapped in organosilica shells by co-hydrolyzation of tetraethylorthosilicate and bis[3-(triethoxysilyl)propyl]disulfide to form core-shell CDs@BONs, where hundreds of CDs are encapsulated in each nanocapsule. Immunofluorescent nanocapsules, i.e. anti-S. Aureus antibody-conjugated CDs@BONs were prepared to specifically recognize S...
January 4, 2018: ACS Applied Materials & Interfaces
M U Anu Prathap, Carlos Iván Rodríguez, Omer Sadak, Jiehao Guan, Vijayasaradhi Setaluri, Sundaram Gunasekaran
We report the development of an antibody (anti-MC1R antibody)-functionalized polyaniline nanofibers modified screen-printed electrode capable of efficient electrochemical detection of melanoma cells at levels (1 cell per mL) not readily achieved by other methods. This immunosensor is highly selective in its detection of melanoma cells over normal human cells.
January 4, 2018: Chemical Communications: Chem Comm
Yan Zeng, Jing Bao, Yanan Zhao, Danqun Huo, Mei Chen, Yanli Qi, Mei Yang, Huanbao Fa, Changjun Hou
Many studies confirm that the aberrant expression of Cytokeratin 19 fragment 21-1 (CYFRA21-1) is highly correlated with non-small cell lung cancer (NSCLC), especially for squamous cell carcinoma. Herein, we report a sandwich-type electrochemical immunosensor based on signal amplification strategy of multiple nanocomposites to test CYFRA21-1 selectively and sensitively. The proposed immunosensor fabricated by three-dimensional graphene (3D-G), chitosan (CS) and glutaraldehyde (GA) composite on the glass carbon electrode (GCE) with a large surface area is prepared to immobilize primary antibodies (Ab1) and provide excellent conductivity...
November 13, 2017: Bioelectrochemistry
Zhen Wu, Wen-Jing Guo, Yi-Yan Bai, Li Zhang, Jiao Hu, Dai-Wen Pang, Zhi-Ling Zhang
Electrochemistry has been widely used to explore fundamental properties of single molecules due to its fast response and high specificity. However, the lack of efficient signal amplification strategies and quantitative method limit its clinical application. Here, we proposed a digital single virus electrochemical enzyme-linked immunoassay (digital ELISA) for H7N9 avian influenza virus (H7N9 AIV) counting by integration of digital analysis, bifunctional fluorescence magnetic nanospheres (bi-FMNs) with monolayer gold nanoparticles (Au NPs) modified microelectrode array (MA)...
December 20, 2017: Analytical Chemistry
Xiaohan Zhang, Huisheng Zhuang
Polycyclic musks (PCMs) in the aquatic environment have become an emerging environmental issue because of their potential risk. The most commonly used method for analysis of PCMs is gas chromatography-mass spectrometer (GC-MS) with different sample extractions, which are somewhat expensive to operate, laborious and complex. In this paper, a carbon nanotube-enhanced real time immuno-PCR was developed for ultrasensitive detection of AHTN in water for the first time. The SWCNTs were used to immobilize numerous amino-DNA and polyclonal antibody to form polyclonal antibody-CNTs-DNA conjugates, which were used as a signal-amplifier in the proposed immunoassay system...
December 16, 2017: Analytical Biochemistry
Helena Kupcova Skalnikova, Jana Cizkova, Jakub Cervenka, Petr Vodicka
Melanoma is a skin cancer with permanently increasing incidence and resistance to therapies in advanced stages. Reports of spontaneous regression and tumour infiltration with T-lymphocytes makes melanoma candidate for immunotherapies. Cytokines are key factors regulating immune response and intercellular communication in tumour microenvironment. Cytokines may be used in therapy of melanoma to modulate immune response. Cytokines also possess diagnostic and prognostic potential and cytokine production may reflect effects of immunotherapies...
December 13, 2017: International Journal of Molecular Sciences
Weiguo Wang, Yake Zou, Jinwu Yan, Jing Liu, Huixiong Chen, Shan Li, Lei Zhang
In this paper, an ultrasensitive colorimetric biosensor for human chorionic gonadotrophin (hCG) detection was designed from bottom-up method based on the dual catalysis of the horseradish peroxidase (HRP) and Au@Pt nanoparticles (NPs) relative to H2 O2 -TEM system. HRP and monoclonal mouse anti-hCG antibody (β-submit, mAb1 ) were co-immobilized onto the Au@Pt NP surface to improve catalytic efficiency and specificity, which formed a dual functionalized Au@Pt-HRP probe with the mean size of 42.8nm (D50 ). The colorimetric immunoassay was developed for the hCG detection, and the Au@Pt-HRP probe featured a higher sensitivity in the concentration range of 0...
March 15, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Colleen N Loynachan, Michael R Thomas, Eleanor R Gray, Daniel A Richards, Jeongyun Kim, Benjamin S Miller, Jennifer C Brookes, Shweta Agarwal, Vijay Chudasama, Rachel A McKendry, Molly M Stevens
Paper-based lateral flow immunoassays (LFIAs) are one of the most widely used point-of-care (PoC) devices; however, their application in early disease diagnostics is often limited due to insufficient sensitivity for the requisite sample sizes and the short time frames of PoC testing. To address this, we developed a serum-stable, nanoparticle catalyst-labeled LFIA with a sensitivity surpassing that of both current commercial and published sensitivities for paper-based detection of p24, one of the earliest and most conserved biomarkers of HIV...
January 23, 2018: ACS Nano
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