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 hp
Sign In
Advertise with Us
LGC Clinical Diagnostics

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

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. More...

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


Gold Member
Universal Transport Solution
Puritan®UniTranz-RT
3-Part Differential Hematology Analyzer
Swelab Alfa Plus Sampler
New
Varicella Zoster Test
ZEUS ELISA Varicella Zoster IgG Test System
New
Uric Acid Meter
PA-16
Read the full article by registering today, it's FREE! It's Free!
Register now for FREE to LabMedica.com and get access to news and events that shape the world of Clinical Laboratory Medicine.
  • Free digital version edition of LabMedica International sent by email on regular basis
  • Free print version of LabMedica International magazine (available only outside USA and Canada).
  • Free and unlimited access to back issues of LabMedica International in digital format
  • Free LabMedica International Newsletter sent every week containing the latest news
  • Free breaking news sent via email
  • Free access to Events Calendar
  • Free access to LinkXpress new product services
  • REGISTRATION IS FREE AND EASY!
Click here to Register








Channels

Hematology

view channel
Image: CitoCBC is the world first cartridge-based CBC to be granted CLIA Waived status by FDA (Photo courtesy of CytoChip)

Disposable Cartridge-Based Test Delivers Rapid and Accurate CBC Results

Complete Blood Count (CBC) is one of the most commonly ordered lab tests, crucial for diagnosing diseases, monitoring therapies, and conducting routine health screenings. However, more than 90% of physician... Read more

Immunology

view channel
Image: The tip optofluidic immunoassay platform enables rapid, multiplexed antibody profiling using only 1 μL of fingertip blood (Photo courtesy of hLife, DOI:10.1016/j.hlife.2025.04.005)

POC Diagnostic Platform Performs Immune Analysis Using One Drop of Fingertip Blood

As new COVID-19 variants continue to emerge and individuals accumulate complex histories of vaccination and infection, there is an urgent need for diagnostic tools that can quickly and accurately assess... Read more

Pathology

view channel
Image: Microscopy image of invasive breast cancer cells degrading their underlying extracellular matrix (Photo courtesy of University of Turku)

Visualization Tool Illuminates Breast Cancer Cell Migration to Suggest New Treatment Avenues

Patients with breast cancer who progress from ductal carcinoma in situ (DCIS) to invasive ductal carcinoma (IDC) face a significantly worse prognosis, as metastatic disease remains incurable.... Read more

Technology

view channel
Image: The machine learning-based method delivers near-perfect survival estimates for PAC patients (Photo courtesy of Shutterstock)

AI Method Predicts Overall Survival Rate of Prostate Cancer Patients

Prostate adenocarcinoma (PAC) accounts for 99% of prostate cancer diagnoses and is the second most common cancer in men globally after skin cancer. With more than 3.3 million men in the United States diagnosed... Read more
Copyright © 2000-2025 Globetech Media. All rights reserved.