Smartphone Enables Detection of Norovirus: Here’s How

A smartphone device has been created that can detect minute amounts of a virus called norovirus. The device, developed by a team of researchers at the University of Arizona, Tucson, USA, is simple, cheap and portable and is capable of detecting minute levels of the virus. The work, which has been published in the American Chemical Society journal ACS Omega, is also being presented at the ACS Fall 2019 National Meeting & Exposition on 25-29 August, 2019 in San Diego, USA.

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Norovirus and its Harmful Effects on Human Health

Norovirus is a notorious and highly contagious virus that causes severe food poisoning, characterized by diarrhea, nausea, vomiting, stomach pain, and abdominal cramps.

Other symptoms include fever, headache and body ache. It is spread by contaminated food and water, particularly seafood such as shellfish. It can also be spread by coming into contact with an infected person. Although usually associated with cruise liners, outbreaks can occur in communities and spread rapidly through the water supply.

Importantly, as few as 10 norovirus particles can cause disease in humans and is responsible for over 20 million cases of food poisoning every year in the US. Norovirus is responsible for approximately 200,000 deaths annually across the globe.

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Study Team

The study was led by Dr. Jeong-Yeol Yoon, PhD, who is the Associate Department Head for Biomedical Engineering Graduate Affairs and Professor of Biomedical Engineering; Professor of Biosystems Engineering; and Professor of Chemistry & Biochemistry at the University of Arizona, Tucson, USA.

Other key team members included Soo Chung, a PhD student in Biosystems Engineering in Yoon’s lab and Professor Kelly A. Reynolds, PhD, who is a Professor of Public Health and Chair of the Department of Community, Environment and Policy at the Mel and Enid Zuckerman College of Public Health, University of Arizona, Tucson, USA.

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What are the Disadvantages of Conventional Testing Methods?

Norovirus is conventionally tested in a laboratory setting, using a variety of high-end, expensive instruments, including microscopes, spectrometers, and lasers. The high cost of these types of equipments is a major disadvantage. Moreover, these cannot be used in field-settings for testing norovirus, such as in cruise liners or municipal water tanks.

What are the Advantages of the New Technology?

As opposed to expensive conventional testing methods, the new technology uses inexpensive materials such as paper-based microfluidic chips and a smartphone, which costs less than USD 50. A major advantage of paper is that it is very cheap and easy to store, thereby making it relatively easy to fabricate the chips. Moreover, as paper is fibrous in nature, it permits the smooth flow of liquid spontaneously without the need for a pumping system that is required for conventional silicon chips.

Another advantage is that the new method detects norovirus by means of fluorescent beads, which attach to the virus surface and can be easily quantitated by counting the fluorescent spots. This alleviates the need for measuring light intensity, which results in background light scattering due to the opaque and porous nature of the paper, thereby making it difficult to detect minute concentrations of the virus.

“You don’t have to be a scientist or an engineer to run the device,” says Yoon. “Analysis will be done automatically by the smartphone app, so all you have to worry about is loading a sample of water onto the chip.”

How is Norovirus Tested Using the New Technology?

The test involves adding a tiny drop of potentially contaminated water at one end of the paper-based microfluidic chip. At the other end of the chip, microscopic polystyrene beads tagged with fluorescent norovirus-specific antibodies are added. If norovirus is present in the water sample, the antibodies attach to the virus and cause clumping or aggregation of the polystyrene beads.

The fluorescence emitted from the aggregated clump of polystyrene beads can be detected and photographed by the smartphone microscope. The smartphone uses an app developed by the researchers to count the illuminated pixels in the image. Each fluorescent pixel represents a clump of beads attached to a single norovirus particle. Therefore, the total number of pixels represents the total number of norovirus particles present in the sample, which makes quantitation very simple and easy.

Concluding Remarks

The research team is hopeful that the new technology can be tweaked so that norovirus infections can be detected early. Moreover, the smartphone platform could be expanded to detect other infectious pathogens, as well as hazardous chemicals including carcinogenic agents.

“Advances in rapid monitoring of human viruses in water are essential for protecting public health,” Reynolds concludes. “This rapid, low-cost water quality monitoring technology could be a transformational tool for reducing both local and global disease burdens.”

Funding Source

The research was funded by the National Science Foundation Water and Environmental Technology (WET) Center, which is an Industry/University Cooperative Research Center (I/UCRC) located at the University of Arizona. Funding was also provided by Tucson Water, which is the Water Department of the City of Tucson.

Reference:

1. Smartphone-Based Paper Microfluidic Particulometry of Norovirus from Environmental Water Samples at the Single Copy Level - (https://pubs.acs.org/doi/10.1021/acsomega.9b00772)

Source-Medindia