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Ultrasensitive immunoassay

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https://www.readbyqxmd.com/read/28505563/ultrasensitive-magnetic-field-assisted-surface-plasmon-resonance-immunoassay-for-human-cardiac-troponin-i
#1
Qiong Wu, Ying Sun, Di Zhang, Shuo Li, Yue Zhang, Pinyi Ma, Yang Yu, Xinghua Wang, Daqian Song
An ultrasensitive surface plasmon resonance (SPR) immunoassay was developed for the specific detection of human cardiac troponin I (cTnI), a principle diagnostic marker for myocardial damage. The thin gold film evaporated on a glass slate, which was employed as the SPR sensing film, was modified by hollow gold nanoparticles (HGNPs) and polydopamine (PDA) sequentially, and then was immobilized with antibodies for specific recognition of target analyte. Electronic coupling of the surface plasmon waves originating from the HGNPs and the gold film leads to the remarkable amplification of SPR response...
May 12, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28495100/ultrasensitive-direct-competitive-flisa-using-highly-luminescent-quantum-dot-beads-for-tuning-affinity-of-competing-antigens-to-antibodies
#2
Sicheng Xiong, Yaofeng Zhou, Xiaolin Huang, Ruijin Yu, Weihua Lai, Yonghua Xiong
Herein, for the first time we report a novel direct competitive fluorescence-linked immunosorbent assay (dcFLISA) for the ultrasensitive detection of ochratoxin A (OTA) by introducing a large size polymer beads loaded with quantum dots (QBs) as carrier of competing antigen for decreasing binding affinity to antibody and enhancing the fluorescent signal intensity. When using 255 nm QBs as carrier of competing antigen, the equilibrium dissociation constant of QB based competing antigen to antibodies can be tuned to 100 times higher than that of the horseradish peroxidase (HRP) based competing antigen by controlling labeled amounts of antigen on the surface of QBs...
June 15, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28488883/ultrasensitive-bioanalysis-current-status-and-future-trends
#3
Stéphanie Simon, Eric Ezan
Ligand-binding techniques such as immunoassays, the reference for clinical diagnosis, offer a wide range of innovative approaches based on signal DNA amplification, nanotechnologies or digital assays, which result in technologies with sensitivities more than 1000-times that of formats used 20 years ago. Providing that these technologies gain acceptance and translate into robust commercial platforms, we expect that several fields will be impacted in the near future, including the clinical diagnosis of cancer markers, the early detection of infectious diseases and the safety of biotherapeutics...
May 10, 2017: Bioanalysis
https://www.readbyqxmd.com/read/28483527/immuno-pcr-with-digital-readout
#4
Hendrik Schröder, Maximilian Grösche, Michael Adler, Mark Spengler, Christof M Niemeyer
Immuno-PCR (IPCR) combines the versatile ELISA antigen detection with ultrasensitive PCR signal amplification, thereby enabling the highly sensitive detection of a broad range of targets with a typically very large dynamic detection range. The quantification of the antigen is usually achieved by real-time PCR, which provides a correlation between the target concentration and amplified DNA marker. We here report on the implementation of digital droplet PCR as a means for direct quantification of DNA copies to enable the highly sensitive detection of protein biomarkers...
May 5, 2017: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/28467848/automated-microfluidic-droplet-based-sample-chopper-for-detection-of-small-fluorescence-differences-using-lock-in-analysis
#5
Jean T Negou, L Adriana Avila, Xiangpeng Li, Tesfagebriel M Hagos, Christopher J Easley
Fluorescence is widely used for small-volume analysis and is a primary tool for on-chip detection in microfluidic devices, yet additional expertise, more elaborate optics, and phase-locked detectors are needed for ultrasensitive measurements. Recently, we designed a microfluidic analog to an optical beam chopper (μChopper) that alternated formation of picoliter volume sample and reference droplets. Without complex optics, the device negated large signal drifts (1/f noise), allowing absorbance detection in a mere 27 μm optical path...
May 11, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28460522/nanobody-based-immunoassay-for-human-soluble-epoxide-hydrolase-detection-using-polymeric-horseradish-peroxidase-polyhrp-for-signal-enhancement-the-rediscovery-of-polyhrp
#6
Dongyang Li, Yongliang Cui, Christophe Morisseau, Shirley J Gee, Candace S Bever, Xiangjiang Liu, Jian Wu, Bruce D Hammock, Yibin Ying
Soluble epoxide hydrolase (sEH) is a potential pharmacological target for treating hypertension, vascular inflammation, cancer, pain, and multiple cardiovascular related diseases. A variable domain of the heavy chain antibody (termed single domain antibody (sdAb), nanobody, or VHH) possesses the advantages of small size, high stability, ease of genetic manipulation, and ability for continuous manufacture, making such nanobody a superior choice as an immunoreagent. In this work, we developed an ultrasensitive nanobody based immunoassay for human sEH detection using polymeric horseradish peroxidase (PolyHRP) for signal enhancement...
May 10, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28451145/competitive-method-based-electrochemiluminescent-assay-with-protein-nucleotide-conversion-for-ratio-detection-to-efficiently-monitor-the-drug-resistance-of-cancer-cells
#7
Wen-Bin Liang, Ming-Zhen Yang, Ying Zhuo, Ying-Ning Zheng, Cheng-Yi Xiong, Ya-Qin Chai, Ruo Yuan
A simple and highly-efficient approach to monitor the expression of P-glycoprotein (P-gp) in cells was urgently needed to demonstrate the drug resistance of cancer cells. Herein, a competitive method-based electrochemiluminescent (ECL) assay with a single ECL indicator was proposed for the first time to efficiently estimate the concentration ratio of two proteins. By converting the different proteins to partially coincident nucleotide sequences via a sandwich type immunoassay on magnetic beads, the concentration ratio related ECL signals could be obtained via competitive nucleotide hybridization on an electrode surface...
December 1, 2016: Chemical Science
https://www.readbyqxmd.com/read/28450781/simple-and-effective-label-free-electrochemical-immunoassay-for-carbohydrate-antigen-19-9-based-on-polythionine-au-composites-as-enhanced-sensing-signals-for-detecting-different-clinical-samples
#8
Zhengjun Huang, Zhouqian Jiang, Chengfei Zhao, Wendi Han, Liqing Lin, Ailin Liu, Shaohuang Weng, Xinhua Lin
Carbohydrate antigen 19-9 (CA19-9) is an important biomarker for the early diagnosis and clinical monitoring of pancreatic cancer. Reliable, simple, and accurate methods for the detection of CA19-9 are still urgently needed. In this study, polythionine-Au composites (AuNPs@ PThi) were designed and prepared through one-pot reaction using HAuCl4 as the co-oxidant and raw material in thionine solution containing FeCl3 as the oxidant. AuNPs@PThi-immobilized glassy carbon electrode was used as a sensitive redox probe for electrochemical interface...
2017: International Journal of Nanomedicine
https://www.readbyqxmd.com/read/28443852/a-biosensor-based-on-self-clickable-aiegen-a-signal-amplification-strategy-for-ultrasensitive-immunoassays
#9
Youyong Yuan, Wenbo Wu, Shidang Xu, Bin Liu
A signal amplified fluorogenic ELISA based on self-clickable fluorogens with aggregation-induced emission characteristics (AIEgen) as a substrate was developed for ultrasensitive immunoassay.
May 9, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28438806/emerging-affinity-based-proteomic-technologies-for-large-scale-plasma-profiling-in-cardiovascular-disease
#10
REVIEW
J Gustav Smith, Robert E Gerszten
Plasma biomarkers that reflect molecular states of the cardiovascular system are central for clinical decision making. Routinely used plasma biomarkers include troponins, natriuretic peptides, and lipoprotein particles, yet interrogate only a modest subset of pathways relevant to cardiovascular disease. Systematic profiling of a larger portion of circulating plasma proteins (the plasma proteome) will provide opportunities for unbiased discovery of novel markers to improve diagnostic or predictive accuracy. In addition, proteomic profiling may inform pathophysiological understanding and point to novel therapeutic targets...
April 25, 2017: Circulation
https://www.readbyqxmd.com/read/28432339/multifunctional-substrate-of-label-free-electrochemical-immunosensor-for-ultrasensitive-detection-of-cytokeratins-antigen-21-1
#11
Huiqiang Wang, Xin Gao, Zhanfang Ma
Poly(thionine)-Au, a novel multifunctional substrate with excellent redox signal, enzyme-like activity, and easy antibody immobilisation, was synthesised using HAuCl4 as the oxidising agent and thionine as the monomer. The prepared poly(thionine)-Au composite exhibited an admirable electrochemical redox signal at -0.15 V and excellent H2O2 catalytic ability. In addition, gold nanoparticles in this composite were found to directly immobilise antibodies and further improve conductivity. In addition, a label-free electrochemical immunosensor was developed using poly(thionine)-Au as the sensing substrate for ultrasensitive detection of cytokeratin antigen 21-1 (CYFRA 21-1), an immunoassay found in human serum...
April 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28411532/one-pot-loading-high-content-thionine-on-polydopamine-functionalized-mesoporous-silica-nanosphere-for-ultrasensitive-electrochemical-immunoassay
#12
Guosong Lai, Min Zheng, Wenjie Hu, Aimin Yu
A thionine (TH)-doped mesoporous silica nanosphere (MSN)/polydopamine (PDA) nanocomposite was synthesized for developing a new signal transduction strategy of electrochemical immunoassay. This nanocomposite was synthesized through one-pot loading of TH and in situ formation of PDA-coating on MSN. After antibody labeling, the obtained nanoprobe was used for the signal tracing of sandwich immunoassay at a magnetic bead-assay platform. Based on the specific capture of the MSN-TH/PDA nanoprobes through sandwich immunoreaction to form a magnetic immunocomplex and the following treatment of the immunocomplex with a NaOH solution, the PDA film coated on MSN was destroyed to release TH tags from the nanoprobe...
September 15, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28411223/modified-bacteriophage-s16-long-tail-fiber-proteins-for-rapid-and-specific-immobilization-and-detection-of-salmonella-cells
#13
Jenna M Denyes, Matthew Dunne, Stanislava Steiner, Maximilian Mittelviefhaus, Agnes Weiss, Herbert Schmidt, Jochen Klumpp, Martin J Loessner
Bacteriophage-based assays and biosensors rival traditional antibody-based immunoassays for detection of low-level Salmonella contaminations. In this study, we harnessed the binding specificity of the long tail fiber (LTF) from bacteriophage S16 as an affinity molecule for immobilization, enrichment, and detection of Salmonella We demonstrate that paramagnetic beads (MBs) coated with recombinant gp37-gp38 LTF complexes (LTF-MBs) are highly effective tools for rapid affinity magnetic separation and enrichment of Salmonella Within 45 minutes, the LTF-MBs consistently captured over 95% of Salmonella Typhimurium cells from suspensions containing 10-10(5) CFU...
April 14, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28391867/ultrasensitive-immunoassay-for-monocrotaline-using-monoclonal-antibody-produced-by-n-n-carbonyldiimidazole-mediated-hapten-carrier-protein-conjugates
#14
Seiichi Sakamoto, Rika Nagamitsu, Gorawit Yusakul, Tomofumi Miyamoto, Hiroyuki Tanaka, Satoshi Morimoto
Monocrotaline (MCT) is a naturally occurring pyrrolizidine alkaloid mainly produced in plant genus Crotalaria (Fabaceae), in which various toxicities have been reported. Recently, demand of quantitative analysis for determination/detection of MCT has increased because MCT in plants can be transferred to human by food chain, leading to intoxication. In this study, monoclonal antibody (MAb) against MCT (MAb 4B8) was produced by unique one-pot conjugation between hydrolysate of MCT, retronecine (RN) and consecutive lysine residues of bovine-serum albumin (BSA) through N,N'-carbonyldiimidazole (CDI) mediated method...
June 1, 2017: Talanta
https://www.readbyqxmd.com/read/28382160/sensitive-detection-of-protein-biomarkers-using-silver-nanoparticles-enhanced-immunofluorescence-assay
#15
Li-Jun Zhao, Ru-Jia Yu, Wei Ma, Huan-Xing Han, He Tian, Ruo-Can Qian, Yi-Tao Long
Detection of biomarkers is extremely important for the early diagnosis of diseases. Here, we developed an easy and highly sensitive fluorescence detection system for the determination of biomarkers by combining the rapid separation of magnetic beads and silver nanoparticles labeled antibodies. An ultrasensitive silver ions fluorescence probe 3', 6'-bis (diethylamino)-2-(2-iodoethyl) spiro[isoindoline-1, 9'-xanthen]-3-one (Ag(+)-FP) was applied to immunoassay. A significant signal amplification was achieved as the AgNPs can be dissolved by H2O2 and generate numerous Ag(+), which would turn "on" the fluorescence of Ag(+)-FP...
2017: Theranostics
https://www.readbyqxmd.com/read/28335966/a-concentration-dependent-multicolor-conversion-strategy-for-ultrasensitive-colorimetric-immunoassay-with-the-naked-eye
#16
Yingshuai Liu, Zeying Zhang, Jie Yu, Jin Xie, Chang Ming Li
Colorimetric immunoassays have been attracting more attention for use in practical applications, especially in point-of-care diagnostics. In comparison with a single color immunoassay, the dose-dependent multicolor strategy greatly improves the detection resolution and accuracy of visual inspection. In the current study, a concentration-dependent multicolor conversion strategy was developed based on gold nanoparticle (AuNP)-mediated copper deposition for signal amplification and Prussian blue for color generation...
April 22, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28317772/ultrasensitive-detection-of-clenbuterol-by-a-covalent-imprinted-polymer-as-a-biomimetic-antibody
#17
Yiwei Tang, Jingwen Gao, Xiuying Liu, Xue Gao, Tao Ma, Xiaonan Lu, Jianrong Li
As an ideal biomimetic antibody, molecularly imprinted polymer (MIP) has shown great promise in immunoassays. Here, we developed a covalent imprinting method to prepare MIP artificial antibody towards clenbuterol on the well surface of a microtiter plate. Template molecule (clenbuterol) was splited by hydrolysis with functional monomer and removed by methanol/acetic acid solution, and then three-dimensional cavities were fabricated in the MIP, which can rebind template molecule via hydrogen bond interaction...
August 1, 2017: Food Chemistry
https://www.readbyqxmd.com/read/28315213/enzyme-linked-immunosorbent-assay-elisa
#18
George N Konstantinou
Food allergy is a public health concern especially after recognizing its constantly increased prevalence and severity. Despite careful reading of food ingredient statements, food allergic individuals may experience reactions caused by "hidden", "masked", or "contaminated" proteins that are known major allergens. Many techniques have been developed to detect even small traces of food allergens, for clinical or laboratory purposes. Enzyme-linked immunosorbent assay (ELISA) is one of the best validated and most routinely used immunoassay in allergy research, in allergy diagnosis in allergy-related quality control in various industries...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28290193/molecularly-imprinted-plasmonic-substrates-for-specific-and-ultrasensitive-immunoassay-of-trace-glycoproteins-in-biological-samples
#19
Pir Muhammad, Xueying Tu, Jia Liu, Yijia Wang, Zhen Liu
Assays of glycoproteins hold significant biological importance and clinical values, for which immunoassay has been the workhorse tool. As immunoassays are associated with disadvantages such as poor availability of high-specificity antibodies, limited stability of biological reagents, and tedious procedure, innovative alternatives that can overcome these drawbacks are highly desirable. Plasmonic immunosandwich assay (PISA) has emerged as an appealing alternative to immunoassay for fast and sensitive determination of trace glycoproteins in biosamples...
March 21, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28225095/high-index-hk0-faceted-platinum-concave-nanocubes-with-enhanced-peroxidase-like-activity-for-an-ultrasensitive-colorimetric-immunoassay-of-the-human-prostate-specific-antigen
#20
Zhuangqiang Gao, Shuzhen Lv, Mingdi Xu, Dianping Tang
Developing simple, high-efficiency non-enzyme bioassays is of great importance for modern analytical systems, but remains a significant challenge. One promising route is to utilize highly efficient nanocatalysts with the exposure of active crystal facets. Herein, we for the first time propose a novel colorimetric immunoassay for the ultrasensitive detection of the human prostate-specific antigen (PSA) based on using a unique type of nanolabel - high-index {hk0} faceted platinum concave nanocubes (HIF-Pt-CNCs)...
March 13, 2017: Analyst
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