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
Technopath Clinical Diagnostics - An LGC Company

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

New
Gold Supplier
Flock Tipped Applicator
HydraFlock 6" Sterile Large Flock Swab w/Polystyrene Handle, 80mm Breakpoint
New
Rapid Fecal Occult Blood (FOB) Test
Advanced Quality Rapid FOB Test
New
Hand-Held Immunoassay & Chemistry Diagnostic System
Nanōmix eLab
New
Pipette Controller
PIPETBOY pro

Print article
MEDLAB - INFORMA

Channels

Molecular Diagnostics

view channel
Image: A novel research study moves the needle on predicting sudden cardiac arrest (Photo courtesy of Pexels)

Newly Identified Protein Biomarkers in Blood Predict Sudden Cardiac Arrest Before it Strikes

Sudden cardiac arrest, or the sudden loss of heartbeat, is a life-threatening heart condition and often fatal. Despite providing an organized emergency medical response, less than 10% of individuals having... Read more

Immunology

view channel
Image: Histopathology of Langerhans cell histiocytosis: The variation in nuclear contours of these cells is evident in this lesion. Classic `kidney bean` nuclei of Langerhans cells with a central groove are present (Photo courtesy of John Lazarchick, MD)

Cooperativity Between Myeloid Lineages Promotes Langerhans Cell Histiocytosis Pathology

Langerhans cell histiocytosis (LCH) is an inflammatory myeloid neoplasia seen in children and adults who present with lesions composed of pathologic variants of myeloid cells that share certain phenotypic... Read more

Microbiology

view channel
Image: Medical illustration of Carbapenem-resistant Enterobacteriacea (Photo courtesy of CDC, Stephanie Rossow)

Breakthrough Test Enables Targeted Antibiotic Therapy for Various Enterobacter Species

Bacteria of the Enterobacter genus are considered to be the most dangerous bacteria linked to hospital infections across the world. Some of their representatives demonstrate high resistance to commonly-used... Read more

Technology

view channel
Image: Flexible copper sensor made cheaply from ordinary materials (Photo courtesy of University of São Paulo)

Low-Cost Portable Sensor Detects Heavy Metals in Sweat

Heavy metals like lead and cadmium can be found in batteries, cosmetics, food and many other things that have become a part of daily life. However, they become toxic if they accumulate in the human body... Read more
Copyright © 2000-2023 Globetech Media. All rights reserved.