Asymmetric bead aggregation for microfluidic immunodetection

Lab on a Chip ◽  
2017 ◽  
Vol 17 (12) ◽  
pp. 2095-2103 ◽  
Author(s):  
Sunggu Kim ◽  
Sanghoon Han ◽  
Junghoon Lee
Keyword(s):  
Magnetic Beads ◽  
Quantitative Detection ◽  
Sliding Motion ◽  
Target Analytes

We present the asymmetric immunoaggregation between polystyrene and magnetic beads, which enables quantitative detection of target analytes via sliding motion in a flow.

Quantum Dots as Fluorescent Labels for Quantitative Detection of Salmonella Typhimurium in Chicken Carcass Wash Water

2005 ◽  
Vol 68 (6) ◽  
pp. 1241-1245 ◽  
Author(s):  
LIJU YANG ◽  
YANBIN LI
Keyword(s):  
Quantum Dots ◽  
Salmonella Typhimurium ◽  
Pathogenic Bacteria ◽  
Magnetic Beads ◽  
Cell Number ◽  
Wash Water ◽  
Quantitative Detection ◽  
Fluorescent Labels ◽  
Microbial Detection ◽  
Chicken Carcass

Fluorescent semiconductor quantum dots have recently emerged as a novel and promising class of fluorescent labels for biological detection. In this study, quantum dots were used as fluorescent labels in immunoassays for quantitative detection of foodborne pathogenic bacteria. Salmonella Typhimurium cells were separated from chicken carcass wash water using anti-Salmonella antibody coated magnetic beads and reacted to secondary biotin-labeled anti-Salmonella antibody. Quantum dots coated with streptavidin were added to react with biotin on the secondary antibody. Measurement of the intensity of fluorescence produced by quantum dots provided a quantitative method for microbial detection. A linear relationship between Salmonella Typhimurium cell number (log N) in the samples of chicken carcass wash water and the fluorescence intensity (FI) was found for the cell numbers ranging from 103 to 107 CFU/ml. The regression model can be expressed as FI = 198.6 Log N − 639.03 with R2 = 0.96. The detection limit of this method was 103 CFU/ml.

scholarly journals Amperometric Detection ofBacillus anthracisSpores: A Portable, Low-Cost Approach to the ELISA

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Gabriel D. Peckham ◽  
Brian E. Hew ◽  
David F. Waller ◽  
Charlie Holdaway ◽  
Michael Jen
Keyword(s):  
Glucose Oxidase ◽  
Magnetic Beads ◽  
Low Cost ◽  
Amperometric Detection ◽  
Signal Generation ◽  
Quantitative Detection ◽  
Laptop Computer ◽  
Electron Mediator ◽  
Fluorescent Signal ◽  
Flow Devices

Antibody-based detection assays are generally robust, a desirable characteristic for in-the-field use. However, to quantify the colorimetric or fluorescent signal, these assays require expensive and fragile instruments which are ill-suited to in-the-field use. Lateral flow devices (LFDs) circumvent these barriers to portability but suffer from poor sensitivity and subjective interpretation. Here, an antibody-based method for detectingBacillus anthracisspores via amperometric signal generation is compared to ELISA and LFDs. This amperometric immunoassay uses antibody conjugated to magnetic beads and glucose oxidase (GOX) along with the electron mediator 2, 6-dichlorophenolindophenol (DCPIP) for production of a measurable current from a 0.4 V bias voltage. With similar sensitivity to ELISA, the assay can be completed in about 75 minutes while being completely powered and operated from a laptop computer. Immunoassay amperometry holds promise for bringing low-cost, quantitative detection of hazardous agents to the field.

scholarly journals New Uses for the Personal Glucose Meter: Detection of Nucleic Acid Biomarkers for Prostate Cancer Screening

Sensors ◽  
2020 ◽  
Vol 20 (19) ◽  
pp. 5514
Author(s):  
Clara Abardía-Serrano ◽  
Rebeca Miranda-Castro ◽  
Noemí de-los-Santos-Álvarez ◽  
María Jesús Lobo-Castañón
Keyword(s):  
Prostate Cancer ◽  
Cancer Screening ◽  
Nucleic Acid ◽  
Magnetic Beads ◽  
Dynamic Range ◽  
Prostate Cancer Screening ◽  
Biological Fluids ◽  
Quantitative Detection ◽  
Personal Glucose Meter ◽  
Glucose Meter

A personal glucose meter (PGM)-based method for quantitative detection of a urinary nucleic acid biomarker in prostate cancer screening, the so-called PCA3, is reported herein. A sandwich-type genoassay is conducted on magnetic beads to collect the target from the sample by specific hybridization, making the assay appropriate for PCA3 detection in biological fluids. The success of the method hinges on the use of alkaline phosphatase (ALP) to link the amount of nucleic acid biomarker to the generation of glucose. In particular, specifically attached ALP molecules hydrolyze D-glucose-1-phosphate into D-glucose, thus enabling the amplification of the recorded signal on the personal glucose meter. The developed genoassay exhibits good sensitivity (3.3 ± 0.2 mg glucose dL−1 pM−1) for PCA3, with a dynamic range of 5 to 100 pM and a quantification limit of 5 pM. Likewise, it facilitates point-of-care testing of nucleic acid biomarkers by using off-the-shelf PGM instead of complex instrumentation involved in traditional laboratory-based tests.

Quantitative detection of ZAP-70 expression in chronic lymphocytic leukemia.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. 6581-6581
Author(s):  
Peixuan Zhu ◽  
Heba A Degheidy ◽  
Gerald E Marti ◽  
Shuhong Li ◽  
Fatima Abbasi ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Magnetic Beads ◽  
Dynamic Range ◽  
Limit Of Detection ◽  
Lymphocytic Leukemia ◽  
Jurkat Cells ◽  
Leukemic Cells ◽  
Quantitative Detection ◽  
Fluorescence Signal ◽  
Wide Range

6581 Background: Intracellular ZAP-70 protein was recently recognized as prognostic marker in chronic lymphocytic leukemia (CLL). The specific objective of this study was to develop a simple and sensitive assay, for the quantitative detection of ZAP-70 protein in leukemic cells. Methods: Components of the assay system include sample preparation, immunomagnetic fluorescence assay, Signalyte-II spectrofluorometer. The leukemic cells were isolated from CLL patient blood samples and lysed to release the intracellular ZAP-70 protein. ZAP-70 protein was captured by magnetic beads coated with anti-ZAP70 capture antibody, and recognized by a fluorescent detector antibody, forming an immuno-sandwich complex. This complex was dissociated for measurement of the fluorescence signal, which was proportional to ZAP-70 concentration, using the spectrofluorometer. Results: The assay conditions were extensively optimized by selecting an optimal pair of capture/detector antibodies, conjugation of fluorescence dye, cell lysis condition and excitation/emission wavelengths. The protocol was further validated with two positive controls, Jurkat cell lysate and recombinant ZAP70 protein (rZAP70). The limit of detection was determined to be lower than 125 Jurkat cells and 39 pg of rZAP70 protein. The signal response was linear over a wide range of concentration, from 625 to 40,000 Jurkat cells per test (R2=0.9987) and from 0 to 40,000 pg rZAP70 protein per test (R2=0.9928). The results from 20 CLL patients correlated strongly with flow cytometry analysis. The concordance between the two methods for positive and negative results was 100% (7/7) and 92% (12/13), respectively, while the overall concordance between the two methods was 95%. Conclusions: The assay is a simple, reliable, and reproducible method for quantitative detection of ZAP-70 in patient leukemic cells, without the need for cell fixation or permeabilization. The entire assay could be completed in 5.5 hours. The ZAP-70 signal was linear over a wide dynamic range, which we believe enables quantitative assessment of small changes in ZAP-70 expression over the course of the disease and in response to therapeutic intervention.

scholarly journals Multiplex Detection of Magnetic Beads Using Offset Field Dependent Frequency Mixing Magnetic Detection

Sensors ◽  
2021 ◽  
Vol 21 (17) ◽  
pp. 5859
Author(s):  
Ali Mohammad Pourshahidi ◽  
Stefan Achtsnicht ◽  
Mrinal Murali Nambipareechee ◽  
Andreas Offenhäusser ◽  
Hans-Joachim Krause
Keyword(s):  
Magnetic Beads ◽  
Programming Algorithm ◽  
Quantitative Detection ◽  
Multiplex Detection ◽  
Mixing Ratios ◽  
Field Dependent ◽  
Sample Amount ◽  
Magnetic Detection ◽  
Mixture Samples ◽  
Frequency Mixing

Magnetic immunoassays employing Frequency Mixing Magnetic Detection (FMMD) have recently become increasingly popular for quantitative detection of various analytes. Simultaneous analysis of a sample for two or more targets is desirable in order to reduce the sample amount, save consumables, and save time. We show that different types of magnetic beads can be distinguished according to their frequency mixing response to a two-frequency magnetic excitation at different static magnetic offset fields. We recorded the offset field dependent FMMD response of two different particle types at frequencies f1 + n⋅f2, n = 1, 2, 3, 4 with f1 = 30.8 kHz and f2 = 63 Hz. Their signals were clearly distinguishable by the locations of the extremes and zeros of their responses. Binary mixtures of the two particle types were prepared with different mixing ratios. The mixture samples were analyzed by determining the best linear combination of the two pure constituents that best resembled the measured signals of the mixtures. Using a quadratic programming algorithm, the mixing ratios could be determined with an accuracy of greater than 14%. If each particle type is functionalized with a different antibody, multiplex detection of two different analytes becomes feasible.

A NEW QUANTITATIVE DETECTION METHOD OF RECOMBINANT CFP10-ESAT6 AMALGAMATION PROTEINS FROM MYCOBACTERIUM TUBERCULOSIS BASED ON MICRO-MAGNETIC PROBES STRATEGY

2012 ◽  
Vol 05 (01) ◽  
pp. 1150007
Author(s):  
YIQING HUANG ◽  
JINPING LUO ◽  
MIXIA WANG ◽  
JUNTAO LIU ◽  
XINXIA CAI
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Magnetic Beads ◽  
Detection Methods ◽  
Quantitative Detection ◽  
Enzyme Linked Immunosorbent Assay ◽  
Chemiluminescence Intensity ◽  
Sandwich Type ◽  
Scientific Significance ◽  
Magnetic Probes ◽  
Higher Sensitivity

A new rapid, specific and sensitive method for assay of recombinant CFP10-ESAT6 amalgamation proteins from Mycobacterium tuberculosis was proposed. The method used streptavidin-coated magnetic beads to enrich the specific biotinylated anti-CFP10 antibody, then adopted a sandwich-type enzyme linked immunosorbent assay technology with two kinds of monoclonal antibodies: biotinylated anti-CFP10 antibody and HRP-labeled anti-CFP10 antibody to identify the target CFP10-ESAT6 proteins, and finally detected chemiluminescence intensity by a small home-made optical sensor. It was shown that, the corresponding chemiluminescence intensity had a good logarithmic linear response to the concentration of CFP10-ESAT6 proteins when ranging at 1 ~ 1000 ng/mL, and the correlation coefficient is 0.9937. The proposed method could detect the CFP10-ESAT6 proteins with low detection limit (1 ng/mL) and the detection time could be controlled within 45 min. Compared with commonly used detection methods of M. tuberculosis, this method was easy to operate, faster, and of higher sensitivity. The achievement of the quantitative detection of CFP10-ESAT6 proteins has important scientific significance and wide application prospects in tuberculosis control.

SERS-based magnetic immunoassay for simultaneous detection of cTnI and H-FABP using core–shell nanotags

2020 ◽  
Vol 12 (45) ◽  
pp. 5442-5449
Author(s):  
Cunming Hu ◽  
Li Ma ◽  
Ming Guan ◽  
Fang Mi ◽  
Fei Peng ◽  
...  
Keyword(s):  
Magnetic Beads ◽  
Reduction Method ◽  
Direct Reduction ◽  
Simultaneous Detection ◽  
Quantitative Detection ◽  
Core Shell

Au-4MBA@Ag and Au-XP013@Ag were successfully synthesized by a direct reduction method. After coupling the antibody, the simultaneous quantitative detection of cTnI and H-ABP was achieved by detecting the signal on the magnetic beads.

scholarly journals Development of a Magnetic Beads Quantitative Detection System for Fast Diagnosis

2010 ◽  
Vol 130 (12) ◽  
pp. 584-589
Author(s):  
Yujiro Yamamoto ◽  
Tomohiro Morishita ◽  
Kenji Matsuyama ◽  
Kenji Takasa ◽  
Ichiro Shibasaki
Keyword(s):  
Magnetic Beads ◽  
Detection System ◽  
Quantitative Detection
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