scholarly journals CRISPR/Cas13a signal amplification linked immunosorbent assay (CLISA)

2019 ◽  
Author(s):  
Qian Chen ◽  
Tian Tian ◽  
Erhu Xiong ◽  
Po Wang ◽  
Xiaoming Zhou
Keyword(s):  
Immunosorbent Assay ◽  
Signal Amplification ◽  
Limit Of Detection ◽  
Enzyme Linked Immunosorbent Assay ◽  
Inflammatory Factor ◽  
Early Diagnosis Of Cancer ◽  
Low Concentrations ◽  
Conventional Elisa ◽  
Amplification Strategy ◽  
Endothelial Growth Factor

ABSTRACTThe enzyme-linked immunosorbent assay (ELISA) is a basic technique used in analytical and clinical investigations. However, conventional ELISA is still not sensitive enough to detect ultra-low concentrations of biomarkers for the early diagnosis of cancer, cardiovascular risk, neurological disorders, and infectious diseases. Herein we show a mechanism utilizing the CRISPR/Cas13a-based signal export amplification strategy, which double-amplifies the output signal by T7 RNA polymerase transcription and CRISPR/Cas13a collateral cleavage activity. This process is termed the CRISPR/Cas13a signal amplification linked immunosorbent assay (CLISA). The proposed method was validated by detecting an inflammatory factor, human interleukin-6 (human IL-6), and a tumor marker, human vascular endothelial growth factor (human VEGF), which achieved limit of detection (LOD) values of 45.81 fg/mL (2.29 fM) and 32.27 fg/m (0.81 fM), respectively, demonstrating that CLISA is at least 102-fold more sensitive than conventional ELISA.

A dual-round signal amplification strategy for colorimetric/photoacoustic/fluorescence triple read-out detection of prostate specific antigen

2020 ◽  
Vol 56 (36) ◽  
pp. 4942-4945 ◽  
Author(s):  
Chao Jiang ◽  
Yan Huang ◽  
Ting He ◽  
Peng Huang ◽  
Jing Lin
Keyword(s):  
Prostate Specific Antigen ◽  
Immunosorbent Assay ◽  
Signal Amplification ◽  
Specific Antigen ◽  
Enzyme Linked Immunosorbent Assay ◽  
Core Shell ◽  
Elisa System ◽  
System P ◽  
Amplification Strategy

A colorimetric/fluorescence/photoacoustic triple read-out detection of prostate specific antigen (PSA) was developed by using a silica coated Au@Ag core–shell nanorod (denoted Au@Ag@SiO2) based enzyme-linked immunosorbent assay (ELISA) system.

Simulation model for predicting limit of detection and range of quantitation of competitive enzyme-linked immunosorbent assay

2007 ◽  
Vol 103 (5) ◽  
pp. 427-431 ◽  
Author(s):  
Dong Hwan Choi ◽  
Yoshio Katakura ◽  
Rieko Matsuda ◽  
Yuzuru Hayashi ◽  
Kazuaki Ninomiya ◽  
...  
Keyword(s):  
Simulation Model ◽  
Immunosorbent Assay ◽  
Limit Of Detection ◽  
Enzyme Linked Immunosorbent Assay

scholarly journals Aflatoxigenic and ochratoxigenic moulds and their toxins in tree nuts on Serbian market

2020 ◽  
pp. 9-18
Author(s):  
Irena Rakic ◽  
Gordana Dimic ◽  
Marija Skrinjar ◽  
Suncica Kocic-Tanackov
Keyword(s):  
Aspergillus Niger ◽  
Ochratoxin A ◽  
Immunosorbent Assay ◽  
Alternaria Alternata ◽  
Rhizopus Oryzae ◽  
Limit Of Detection ◽  
Average Concentration ◽  
Enzyme Linked Immunosorbent Assay ◽  
Mean Values ◽  
Tree Nuts

In this study, moulds and mycotoxins presence in different tree nuts were investigated. The results showed that all of the 25 samples were contaminated with moulds. Mean values of total mould count varied from 1-4.9 cfu per grain. The most frequent species in hazelnut samples were Rhizopus oryzae (32.2%) and Aspergillus niger (28.9%). In walnuts A. niger (75.6%), in cashews also A. niger (42.4%) while in pistachio samples Alternaria alternata (20.7%), and Cladosporium cladosporioides (20.7%) were the most dominant. Rhizopus oligosporus was the only identified species in all almond samples (100%). Using Enzyme Linked Immunosorbent Assay (ELISA), the presence of total aflatoxins and ochratoxin A was examinated. In all analyzed samples, levels of ochratoxin A were below the limit of detection. Total aflatoxins were detected only in walnut samples with average concentration of 7.1 ?g/kg.

scholarly journals A novel electrochemical aptasensor for fumonisin B1 determination using DNA and exonuclease-I as signal amplification strategy

BMC Chemistry ◽  
2019 ◽  
Vol 13 (1) ◽  
Author(s):  
Min Wei ◽  
Fei Zhao ◽  
Shuo Feng ◽  
Huali Jin
Keyword(s):  
Incubation Time ◽  
Electrode Surface ◽  
Signal Amplification ◽  
Limit Of Detection ◽  
Fumonisin B1 ◽  
Electrochemical Aptasensor ◽  
Experimental Conditions ◽  
Exonuclease I ◽  
Double Stranded Dna ◽  
Amplification Strategy

Abstract In this work, using DNA and exonuclease-I (Exo-I) as signal amplification strategy, a novel and facile electrochemical aptasensor was constructed for fumonisin B1 (FB1) detection. The G-rich complementary DNA (cDNA) was immobilized onto the electrode surface. Then, aptamer of FB1 was hybridized with cDNA to form double-stranded DNA. In the absence of FB1, double-stranded DNA and G-rich cDNA on the electrode surface promoted effectively methylene blue (MB) enrichment and amplified the initial electrochemical response. In the presence of FB1, the combination of aptamer and FB1 led to the release of aptamer from the electrode surface and the expose of 3′ end of single-stranded cDNA. When Exo-I was added onto the electrode surface, the single-stranded cDNA was degraded in the 3′–5′ direction. The decrease of double-stranded DNA and G-rich cDNA resulted in the less access of MB to the electrode surface, which decreased the electrochemical signal. The experimental conditions including incubation time of FB1, the amount of Exo-I and incubation time of Exo-I were optimized. Under the optimal conditions, the linear relationship between the change of peak current and the logarithmic concentration of FB1 was observed in the range of 1.0 × 10−3–1000 ng mL−1 with a low limit of detection of 0.15 pg mL−1. The experimental results showed that the prepared aptasensor had acceptable specificity, reproducibility, repeatability and stability. Therefore, this proposed aptasensor has a potential application in the food safety detection.

A novel signal amplification strategy for highly specific and nonenzymatic isothermal electrochemiluminescence detection of tumour markers

2020 ◽  
Vol 12 (7) ◽  
pp. 938-942 ◽  
Author(s):  
Yan Liu ◽  
Xin Guo ◽  
Zhijin Fan ◽  
Yuhui Liao ◽  
Ying Yu ◽  
...  
Keyword(s):  
Signal Amplification ◽  
Limit Of Detection ◽  
Tumour Markers ◽  
Linear Dna ◽  
Amplification Strategy

A signal amplification strategy for highly specific and nonenzymatic isothermal electrochemiluminescence detection of microRNA was developed. The limit of detection was as low as 4 fmol, which was superior to that for the reported linear DNA method.

Immunoassay for human serum hepcidin

Blood ◽  
2008 ◽  
Vol 112 (10) ◽  
pp. 4292-4297 ◽  
Author(s):  
Tomas Ganz ◽  
Gordana Olbina ◽  
Domenico Girelli ◽  
Elizabeta Nemeth ◽  
Mark Westerman
Keyword(s):  
Healthy Volunteers ◽  
Immunosorbent Assay ◽  
Limit Of Detection ◽  
Deficiency Anemia ◽  
Enzyme Linked Immunosorbent Assay ◽  
Reactive Protein ◽  
Transient Rise ◽  
Juvenile Hemochromatosis ◽  
Serum Hepcidin ◽  
Clinical Conditions

Abstract We developed and validated the first serum enzyme-linked immunosorbent assay for hepcidin, the principal iron-regulatory hormone that has been very difficult to measure. In healthy volunteers, the 5% to 95% range of hepcidin concentrations was 29 to 254 ng/mL in men (n = 65) and 17 to 286 ng/mL in women (n = 49), with median concentrations 112 versus 65 (P < .001). The lower limit of detection was 5 ng/mL. Serum hepcidin concentrations in 24 healthy subjects correlated well with their urinary hepcidin (r = 0.82). Serum hepcidin appropriately correlated with serum ferritin (r = 0.63), reflecting the regulation of both proteins by iron stores. Healthy volunteers showed a diurnal increase of serum hepcidin at noon and 8 pm compared with 8 am, and a transient rise of serum hepcidin in response to iron ingestion. Expected alterations in hepcidin levels were observed in a variety of clinical conditions associated with iron disturbances. Serum hepcidin concentrations were undetectable or low in patients with iron deficiency anemia (ferritin < 10 ng/mL), iron-depleted HFE hemochromatosis, and juvenile hemochromatosis. Serum hepcidin concentrations were high in patients with inflammation (C-reactive protein > 10 mg/dL), multiple myeloma, or chronic kidney disease. The new serum hepcidin enzyme-linked immunosorbent assay yields accurate and reproducible measurements that appropriately reflect physiologic, pathologic, and genetic influences, and is informative about the etiology of iron disorders.

A Monoclonal Antibody-Based Enzyme-Linked Immunosorbent Assay for Determination of Homoharringtonine

Planta Medica ◽  
2018 ◽  
Vol 84 (14) ◽  
pp. 1038-1044 ◽  
Author(s):  
Benyakan Pongkitwitoon ◽  
Seiichi Sakamoto ◽  
Rika Nagamitsu ◽  
Waraporn Putalun ◽  
Hiroyuki Tanaka ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Immunosorbent Assay ◽  
Myeloid Leukemia ◽  
High Performance ◽  
Sodium Periodate ◽  
Limit Of Detection ◽  
Enzyme Linked Immunosorbent Assay ◽  
Study Support ◽  
Mediated Oxidation

AbstractHomoharringtonine (HHT), also known as omacetaxine, is a natural compound found in the genus Cephalotaxus and is a promising pharmaceutical drug used for the treatment of chronic or accelerated phase chronic myeloid leukemia. As a tool for the quantitative determination of HHT, a specific monoclonal antibody against HHT (MAb 6A1) was generated by conjugates prepared via sodium periodate-mediated oxidation. The developed indirect competitive enzyme-linked immunosorbent assay (icELISA) using MAb 6A1 was found to be highly specific and sensitive with a limit of detection for HHT of 48.8 ng/mL. Validation assays to evaluate precision and accuracy of the method were conducted by the use of intra- and inter-assay analysis, recovery test, and comparison analysis between the amounts of HHT determined by ELISA and high-performance liquid chromatography. These results revealed that the established icELISA using MAb 6A1 is specific, sensitive, and reliable enough to be applied to the qualitative analysis for HHT. Furthermore, the results of this study support the usefulness of sodium periodate as a reagent for the conjugation between Cephalotaxus alkaloids and proteins for producing specific antibodies.

Trastuzumab (T) detection in serum using signal amplification strategy for non-faradaic impedimetric sensing quartz crystal microbalance (QCM) based on peptide piezo-immunosensors and its role in breast cancer treatment.

2017 ◽  
Vol 35 (15_suppl) ◽  
pp. e12502-e12502
Author(s):  
Mohammad Muhsin Chisti ◽  
Juan Liu ◽  
Justin Frank Antoni Klamerus ◽  
Ishmael A. Jaiyesimi ◽  
Syeda Hina Batool ◽  
...  
Keyword(s):  
Real Time ◽  
Signal Amplification ◽  
Limit Of Detection ◽  
Cell Immobilization ◽  
Breast Cancers ◽  
Label Free ◽  
Faradaic Impedance ◽  
Free Peptide ◽  
Capacitive Biosensor ◽  
Amplification Strategy

e12502 Background: Her2Neu (H) antigen, expressed on 20% of Breast cancers, is an established target for antibody therapy with T. Immunohistochemistry is still the most widely used technique to detect h level which is time consuming and does not reveal any details of interaction between the molecules. We have developed a new innovative biosensor based novel technique to study real time interaction of h antigens with T using QCM Piezo-immunosensor. This quantitative label free peptide based assay can be used to characterize cell surface antigen, to study antigen- antibody interactions and obtain understanding of mechanisms of resistance. Methods: A label free and reagent free peptide mimotope capacitive biosensor is developed for T quantification based on non-Faradaic readout. The low sensitivity issue of capacitive biosensor was overcome with two innovations: peptide mimotope mixed SAM biointerface and dilution of the testing buffer. Signal amplification was achieved through dilution of the PBS buffer to tune Cdl to dominate the overall capacitance change upon target binding. After 1000 times dilution, limit of detection is lowered 500 times (0.22 µg/mL) and the sensitivity increased 20 times (0.04192 (µg/mL)-1). Results: Binding was very specific. Signal amplification strategy is practical. Further applied to planar electrode for optimizing sensing, response time in less than 1 minute. Conclusions: This is the first report of T detection using electrochemical method based on non-Faradaic impedance. h antigen density and interactions of antigens will help physicians to determine the clinical efficacy and resistance mechanisms to targeted antibodies like T and ado-Trastuzumab.For the first time, we have established a low cost, highly sensitive, fast, synthetic, QCM assay which could be used as a basis for developing a new generation of affinity-based Immunosensor assays. This real time capability and its simplicity of operation are highly suitable for multipurpose studies on living cells including cell immobilization, cytotoxicity of drugs, and the cell action mechanisms

scholarly journals Development of an antigen-capture enzyme-linked immunosorbent assay for Clostridium perfringens beta2-toxin in porcine feces and the neonatal piglet intestine

2012 ◽  
Vol 24 (5) ◽  
pp. 895-902 ◽  
Author(s):  
Jasmina Kircanski ◽  
Douglas Hodgins ◽  
Glenn Soltes ◽  
Yanlong Pei ◽  
Valeria R. Parreira ◽  
...  
Keyword(s):  
Immunosorbent Assay ◽  
Protease Activity ◽  
Limit Of Detection ◽  
Intestinal Content ◽  
Enzyme Linked Immunosorbent Assay ◽  
Neonatal Piglet ◽  
Antigen Capture ◽  
Field Samples ◽  
Intestinal Contents ◽  
Beta2 Toxin

An enzyme-linked immunosorbent assay (ELISA) was developed for detection and quantitation of beta2-toxin in neonatal piglet intestinal contents. Polystyrene plates were coated with polyclonal capture antibodies prepared against consensus recombinant beta2-toxin. The ELISA was developed using consensus recombinant beta2-toxin, atypical recombinant beta2-toxin, purified consensus native beta2-toxin, and field samples of neonatal porcine intestinal contents. Captured antigen was detected using a horseradish peroxidase–labeled monoclonal antibody against consensus recombinant beta2-toxin. The limit of detection of the ELISA for consensus beta2-toxin was between 2.0 and 3.5 ng/ml. The ELISA detected atypical recombinant beta2-toxin only weakly. Optical density was protein concentration dependent. The test confirmed differences between consensus and atypical recombinant beta2-toxin, but similar results obtained when testing pure consensus recombinant beta2-toxin and native beta2-toxin. Results obtained from intestinal content samples, particularly from the small intestine, were highly inconsistent and suggested variable protease activity. Addition of protease inhibitors partially prevented degradation of the toxin; however, sample processing at low temperature, at a lower pH (citrate buffer with 5% of bovine serum albumin, pH 6.1), and “cold incubation” of applied antigens abolished protease activity. The recombinant toxin was preserved in spiked intestinal samples by freezing at −70°C, suggesting that necropsy samples can be stored frozen for periodic testing. With appropriate sample preparation, antigen-capture ELISA can detect beta2-toxin in the intestinal content and feces of neonatal piglets.

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