We use cookies to understand how you use our site and to improve your experience. This includes personalizing content and advertising. To learn more, click here. By continuing to use our site, you accept our use of cookies. Cookie Policy.

Features Partner Sites Information LinkXpress
Sign In
Advertise with Us
PURITAN MEDICAL

Download Mobile App





New Immunosensor Paves Way to Rapid POC Testing for COVID-19 and Emerging Infectious Diseases

By LabMedica International staff writers
Posted on 19 Dec 2022
Print article
Image: Detecting SARS-CoV-2 with a new Quenchbody immunosensor (Photo courtesy of Tokyo Tech)
Image: Detecting SARS-CoV-2 with a new Quenchbody immunosensor (Photo courtesy of Tokyo Tech)

The incredibly fast spread of COVID-19 throughout the world brought to light a very important fact: we need better methods to diagnose infectious diseases quickly and efficiently. During the early months of the pandemic, polymerase chain reaction (PCR) tests were one of the most widely used techniques to detect COVID-19. However, these viral RNA-based techniques require expensive equipment and reaction times longer than an hour, which renders them less than ideal for point-of-care testing. The limitations of PCR fueled the development of various immunoassay methods, which use specially engineered antibodies to detect SARS-CoV-2 antigens with high sensitivity in little time. Today, scientists are still improving immunoassay technology to make available tools more convenient, sensitive, and cost-effective. Against this backdrop, a team of researchers has developed a new immunosensor based on Quenchbody technology that shows great potential as a fast, inexpensive, and convenient tool to detect SARS-CoV-2. This highly efficient diagnostic approach will be useful not only for point-of-care testing, but also for high-throughput epidemiological studies of COVID-19 and other emerging infectious diseases.

The team of researchers at Tokyo Institute of Technology (Tokyo Tech, Tokyo, Japan) has not only developed a new Quenchbody fluorescent immunosensor that can detect SARS-CoV-2 with exceptional speed and sensitivity, but also created a simple way to greatly enhance the immunosensor's performance using a crowding agent. A Quenchbody is a molecular sensor originally developed by Professor Ueda and colleagues using antibody fragments and fluorescent tags. The antibody fragment, which can be an antigen-binding region (or 'Fab'), targets a specific viral molecule (antigen). Meanwhile, the fluorescent tags are small fluorescent dye molecules attached by a peptide linker to the Quenchbody, near the antigen-binding region. When the antigen is absent, the fluorescent tags are attracted to the Fab and intrinsic amino acids (mainly tryptophan) interact with the dyes and quench the fluorescence. However, when the antigen appears, it replaces the fluorescent tag at the Fab, causing it to move away and recover its fluorescence. Thus, in a Quenchbody test, an increase in fluorescence indicates the detection of the target antigen.

In this study, the research team developed a double-tagged Quenchbody targeting the nucleocapsid protein (N protein) of SARS-CoV-2. To take things one step further, they also tested whether various commercially available compounds could improve the immunosensor's sensitivity and detection time. In particular, adding polyethylene glycol 6000 (PEG6000) at the right concentration as a crowding agent increased performance quite significantly. To further validate their approach, the team tested their immunosensor on leftover clinical samples from COVID-19 positive patients. After careful analysis of the results, they concluded that their newly developed Quenchbody could measure N protein more easily and quantitatively than a commercial lateral flow antigen test.

"Our work shows the feasibility of using Quenchbody immunosensors as rapid and cost-efficient tools for the diagnosis and high-throughput analysis of swab samples in large-scale monitoring and epidemiological studies of COVID-19, as well as other emerging infectious diseases," said Professor Hiroshi Ueda at Tokyo Tech who led the research.

Related Links:
Tokyo Tech

Flocked Swab
HydraFlock and PurFlock Ultra
Gold Supplier
Multiplex Genetic Analyzer
MassARRAY Dx Analyzer
New
PCR Fluorescent Quantitative System
AccuRa mini
New
Herpes Simplex Virus Test
S3002E HSV-2

Print article

Channels

Clinical Chem.

view channel
Image: Electrochemical cells etched by laser on wooden tongue depressor measure glucose and nitrite in saliva (Photo courtesy of Analytical Chemistry)

Biosensor-Fabricated Wooden Tongue Depressor Measures Glucose and Nitrite in Saliva

Physicians often use tongue depressors to examine a patient's mouth and throat. However, it is hard to imagine that this simple wooden tool could actively assess a patient's health. This idea has led to... Read more

Hematology

view channel
Image: The Atellica HEMA 570 and 580 hematology analyzers remove workflow barriers (Photo courtesy of Siemens)

Next-Gen Hematology Analyzers Eliminate Workflow Roadblocks and Achieve Fast Throughput

Hematology testing is a critical aspect of patient care, utilized to establish a patient's health baseline, track treatment progress, or guide timely modifications to care. However, increasing constraints... Read more

Immunology

view channel
Image: Newly observed anti-FSP antibodies have also been found to predict immune-related adverse events (Photo courtesy of Calviri)

First Blood-Based Biomarkers Test to Predict Treatment Response in Cancer Patients

Every year worldwide, lung cancer afflicts over two million individuals and almost the same number of people succumb to the disease. This malignancy leads the charts in cancer-related mortalities, with... Read more

Microbiology

view channel
Image: The rapid MTB strip test for tuberculosis can identify TB patients within two hours (Photo courtesy of Chulalongkorn University)

Rapid MTB Strip Test Detects Tuberculosis in Less Than an Hour without Special Tools

Tuberculosis (TB), a highly infectious disease, continues to pose significant challenges to public health worldwide. TB is caused by a bacterium known as "Mycobacterium tuberculosis," spreading through... Read more

Pathology

view channel
Image: The UNIQO 160 (CE-IVDR) advances diagnostic analysis for autoimmune diseases (Photo courtesy of EUROIMMUN)

Novel Automated IIFT System Enables Cutting-Edge Diagnostic Analysis

A newly-launched automated indirect immunofluorescence test (IIFT) system for autoimmune disease diagnostics offers an all-in-one solution to enhance the efficiency of the complete IIFT process, comprising... Read more

Technology

view channel
Electronic biosensor uses DNA aptamers for detecting biomarkers in whole blood samples (Photo courtesy of Freepik)

Electronic Biosensor Detects Biomarkers in Whole Blood Samples without Addition of Reagents

The absence of robust, reliable, and user-friendly bioanalytical tools for early and timely diagnosis of cardiovascular diseases, particularly sudden cardiac arrest, leads to preventable deaths and imposes... Read more

Industry

view channel
Image: The global HbA1c testing devices market is expected to reach USD 2.56 billion in 2027 (Photo courtesy of Freepik)

Global Hemoglobin A1c Testing Devices Market Driven by Rising Prevalence of Diabetes

Hemoglobin A1c (HbA1c), or glycated hemoglobin, refers to hemoglobin with glucose attached. HbA1c testing devices are used for blood tests that determine average blood glucose, or blood sugar levels.... Read more
Copyright © 2000-2023 Globetech Media. All rights reserved.