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

Download Mobile App





Cheap 5-Minute COVID-19 Test Accurately Detects SARS-CoV-2 Antibody in Blood or Saliva

By LabMedica International staff writers
Posted on 17 Sep 2021
Researchers have developed an ultrafast, low-cost, label-free, and portable SARS-CoV-2 immunoglobulin G (IgG) detection platform based on organic electrochemical transistors (OECTs), which can be remotely controlled by a mobile phone.

The device developed by researchers at The Hong Kong Polytechnic University (Hong Kong) can detect SARS-CoV-2 IgG with an ultralow detection limit of 1 fM in aqueous solutions and 10 fM in serum and saliva within five minutes.

Currently, COVID-19 antibodies are detected mainly by enzyme-linked immunosorbent assay (ELISA) and colloidal gold lateral flow immunoassays (LFIAs). More...
ELISA is highly accurate, but the technical procedure is complicated, making it difficult to achieve both portable and high-throughput detection. LFIA is easy to operate and portable, but with relatively low sensitivity and prone to misdiagnosis. Therefore, for the detection of COVID-19 antibody, there is a need to develop a highly sensitive and rapid detection method that can be easily operated for point-of-care testing and screening of large populations. In addition to serum-based assays, SARS-CoV-2 IgG can be detected in saliva, with the advantages of a noninvasive process and the possibility of self-collection of samples. Because antibody concentration in human saliva is several orders of magnitude lower than in serum, high analytical sensitivity is needed

Organic electrochemical transistors (OECTs) have been recognized as high-performance transducers and amplifiers that can convert biological signals into electrical signals. OECT-based biosensors have the advantages of high sensitivity, low cost, easy fabrication, and mechanical flexibility and are suitable for high-throughput and multiplexing detections of biomarkers. In recent years, OECTs have been successfully used in the detection of various biomolecules, including nucleic acids, proteins, and metabolite.

In the latest study, the researchers used OECT-based biosensors for the detection of SARS-CoV-2 IgG that is controlled by a portable meter and a mobile phone through Bluetooth. The team developed portable, label-free, and low-cost biosensors based on OECTs for rapid and highly sensitive detections of SARS-CoV-2 IgG. The gate electrodes of the OECTs were modified with SARS-CoV-2 spike proteins that can selectively capture the IgG through the specific antibody-antigen reaction. The positively charged IgG molecules in aqueous solutions form electrical dipoles on gate surfaces and modulate the channel currents of the OECTs. By optimizing the measurement conditions, including electrolyte ion concentration and pH value, high device sensitivity was achieved. The detection limits of the devices can reach 1 fM in aqueous solutions and 10 fM in saliva and serum samples, which are much better than many existing electrochemical methods. Notably, the detectable region can cover the concentrations of the specific antibody in the serum and saliva of patients with COVID-19, promising a high potential for practical applications. Faster detection of IgG has been realized by applying voltage pulses on the gates of OECTs during incubation, and stable signal can be obtained within five minutes. The testing process can be remotely operated with a mobile phone by controlling a portable meter via Bluetooth, which can meet the requirement of fast and point-of-care detections of COVID-19 antibody. In addition to COVID-19 antibody, the biosensor can also be used in the fast detections of many other diseases that may generate antibodies.

Related Links:
The Hong Kong Polytechnic University


Gold Member
Multiplex Genetic Analyzer
MassARRAY Dx Analyzer (Europe only)
Portable Electronic Pipette
Mini 96
New
Gold Member
Immunochromatographic Assay
CRYPTO Cassette
Specimen Radiography System
TrueView 200 Pro
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

Molecular Diagnostics

view channel
Image: AiPlex VAS for the MosaiQ platform is designed to help reduce time-to-diagnosis for patients with autoimmune vasculitis (Photo courtesy of AliveDx)

Novel Multiplex Assay Supports Diagnosis of Autoimmune Vasculitis

Autoimmune vasculitis and related conditions are difficult to diagnose quickly and accurately, often requiring multiple tests to confirm the presence of specific autoantibodies. Traditional methods can... Read more

Hematology

view channel
Image: New research points to protecting blood during radiation therapy (Photo courtesy of 123RF)

Pioneering Model Measures Radiation Exposure in Blood for Precise Cancer Treatments

Scientists have long focused on protecting organs near tumors during radiotherapy, but blood — a vital, circulating tissue — has largely been excluded from dose calculations. Each blood cell passing through... Read more

Immunology

view channel
Image: The test could streamline clinical decision-making by identifying ideal candidates for immunotherapy upfront (Xiao, Y. et al. Cancer Biology & Medicine July 2025, 20250038)

Blood Test Predicts Immunotherapy Efficacy in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is an aggressive subtype lacking targeted therapies, making immunotherapy a promising yet unpredictable option. Current biomarkers such as PD-L1 expression or tumor... Read more

Technology

view channel
Image: The sensor can help diagnose diabetes and prediabetes on-site in a few minutes using just a breath sample (Photo courtesy of Larry Cheng/Penn State)

Graphene-Based Sensor Uses Breath Sample to Identify Diabetes and Prediabetes in Minutes

About 37 million U.S. adults live with diabetes, and one in five is unaware of their condition. Diagnosing diabetes often requires blood draws or lab visits, which are costly and inconvenient.... Read more
Copyright © 2000-2025 Globetech Media. All rights reserved.