By: Shruti Chowdhari

New tool to detect viruses quickly at low cost

It takes over Rs 10,000 and over 24 hours to detect the presence of chikungunya, dengue or H1N1 virus in the body. US scientists have developed a biosensor that could detect viruses in 30 minutes and would cost about a dollar (Rs 45).

Pathologists use ELISA (enzymelinked immunosorbant assays) and PCR (polymerase chain reaction) tests to scan blood samples for antigens or antibodies that are produced as an immune response to virus attack. These tools, though effective, require significant lab infrastructure and time as they involve cell culture and sample preparation. The new tool, optofluidic nanoplasmonic biosensor, requires just a metal wafer with arrays of 200-350-nanometre wide apertures and light, said the researchers at Boston University.

They coated the sensor with antibodies specific to a group of viruses and put a sample of blood on it. The viruses in the sample got caught by antibodies and stuck to the nanoholes. This binding changed the refractive index of the sensor, meaning the speed and the amount of light passing through the sensor got changed. The magnitude of the shift reveals the presence and concentration of the virus, the researchers noted in the November issue of Nano Letters.

Though in its infancy, the researchers said, the biosensor will lead to the development of low-cost, quick-detection tools, which can help confine outbreaks of fast-spreading viruses like swine flu and avert bioterrorism attacks using pathogens like Ebola virus.