New low-cost Zika test looks good on paper

The paper-based test changes color to clearly show the presence of a virus: purple for positive, yellow for negative

Researchers have developed a low-cost, paper-based method of detecting viruses like Zika and Ebola in a biological sample, and which can even identify a specific strain. The team believes the test can be used in the field to quickly and easily detect the presence of a virus, and be used to help slow the spread of future outbreaks.

Developed by a multi-institutional research team led by synthetic biologist James Collins, Ph.D., at Harvard University's Wyss Institute, the test is a low-cost, resource-efficient process designed to be carried out in the field. It consists of a synthetic biomolecular sensor that is embedded into a paper disc, which is then used to screen a sample of blood, urine or saliva. If an RNA sequence associated with a particular virus is detected, the sensors will change color: purple for positive, yellow for negative.

The test involves a three-step process. The first step, amplification, is required because the concentration of the virus in a sample is extremely low, and initially hard to detect. To combat this, a sample's RNA must first be amplified using a mixture of enzymes and "primers", which are DNA sequences which trigger replication into a measurable concentration.

After that, the sample can be applied to the paper discs to activate the freeze-dried components. Within 30 to 60 minutes the color change will indicate whether the patient is infected with the virus or not. If results are required faster than that, an electronic reader can also analyze the sample.

If a virus is detected, a third step can determine which particular strain is present. A gene-editing mechanism known as CRISPR-Cas9 searches the sample for specific genetic markers that indicate the strain of the virus, and present that information through another color change.

The best part is the method could eventually be adapted to search for any RNA-based virus, including Zika, Ebola, SARS, measles, influenza, hepatitis C and West Nile fever.

"In response to an emerging outbreak, we envision a custom-tailored diagnostic system could be ready for use within one week's time," says Collins. "We are currently pursuing multiple opportunities to secure private and public funding in order to commercialize this diagnostic system and make it available to the world's health responders."

The researchers explain the test in the video below.

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