According to a recent study published in ACS Sensors, researchers have created a prototype sensor that can identify the H5N1 influenza virus in air samples. The inexpensive handheld sensor, which can identify the virus at concentrations below an infectious dose, may result in rapid aerosol testing for airborne avian influenza.
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Recent outbreaks have resulted in the need for rapid and sensitive detection techniques to stop the spread of highly pathogenic avian influenza, commonly referred to as bird flu.
Bird flu can spread rapidly when birds and other animals inhale infectious respiratory droplets, and airborne transmission to humans is a concern due to the virus's frequent mutations. Current techniques for detecting H5N1 viruses, like polymerase chain reaction (PCR)-based tests, frequently call for a large amount of sample preparation in a laboratory. Thus, before an outbreak, a sensor that can swiftly identify these airborne viral particles without sample preparation could detect transmission.
The electrochemical capacitive biosensor (ECB), which has been effectively used to identify other airborne viruses, may be one solution. An electrochemical biosensor was previously developed by a research team under the direction of Rajan Chakrabarty to identify SARS-CoV-2 particles in breath. This time, the team measured and identified the amount of H5N1 viruses in the air using ECB technology.
The new ECB is made up of a screen-printed carbon electrode with a thin network of graphene oxide branches and Prussian blue nanocrystals. The researchers connected probes (aptamers or antibodies) sensitive to H5N1 viruses to the network to enable the sensor to detect these viruses.
They combined the sensor with a specially designed air sampler, which collects airborne droplets and produces a liquid sample. When liquid samples containing H5N1 viruses were introduced to the sensor, the viral particles attached to the probes, altered the sensor’s capacitance. The researchers were able to determine the amount of H5N1 present in the liquid sample by measuring the total change in capacitance.
The ECB demonstrated results in five minutes using aerosolized samples that contained known amounts of inactivated H5N1 viruses. According to the researchers, the sensor's avian influenza detection level of 93 viral copies per 35 cubic feet (1 cubic meter) of air should be "sensitive enough to detect the presence of H5N1 below the virus’ infectious dose."
The sensor's overall accuracy was over 90% compared to measurements from a digital PCR test, the conventional method. According to Chakrabarty and the team, the new bird flu sensor holds promise for real-time, noninvasive air monitoring of both human and animal populations.
The Flu Lab supported the study.
Journal Reference:
Kumar, J., et al. (2025) Capacitive Biosensor for Rapid Detection of Avian (H5N1) Influenza and E. coli in Aerosols. ACS Sensors. doi/10.1021/acssensors.4c03087?goto=supporting-info