IISER Pune Scientists Develop 20-Minute Low-Cost RNA Test for Covid-19 and Zika Detection

Paper-based colour test delivers results in 20 minutes; potential game-changer for rural diagnostics and future pandemics

In a major breakthrough in public health diagnostics, a research team from the Indian Institute of Science Education and Research (IISER), Pune has developed an ultra-low-cost RNA sensor capable of detecting Covid-19 and Zika viruses within 20 minutes and without the need for high-end lab infrastructure.

The findings, published on May 29, 2025, in the journal ACS Synthetic Biology, demonstrate how toehold switches, a synthetic biology tool, can be engineered to improve sensitivity and speed in RNA-based diagnostics. The technology, if scaled, promises to make viral testing faster, cheaper, and accessible, especially in underserved and remote regions.

A Rapid, Paper-Based Test with Visible Results

The novel biosensor system involves engineered RNA switches that react to the presence of specific viral RNA sequences, in this case, from Covid-19 and Zika. When a patient sample is dropped onto a small paper disc embedded with the biosensor, a visible colour change indicates the presence of the virus. The test detects viral RNA at picomolar concentrations (10⁻¹² M), offering reliable early detection even at low viral loads.

According to Dr. Chaitanya Athale, a senior researcher on the project, “The major advantage is that this method doesn’t require advanced instruments like RT-PCR machines or expert interpretation. It can be run by a minimally trained technician in the field.”

Addressing Gaps in Testing Infrastructure

During the 2021 second wave of the Covid-19 pandemic, RT-PCR test shortages and limited lab availability hampered timely diagnoses in many parts of India. This experience led the IISER team to focus on decentralized diagnostic solutions.

“RT-PCR remains the gold standard in sensitivity, but it depends on central labs, machines, and trained personnel. In contrast, our biosensor test is portable, inexpensive, and ideal for point-of-care deployment,” Athale explained.

The researchers envision the test being used in rural clinics, community centers, or even home-based setups, essentially anywhere lab support is minimal or absent.

The prototype test has been validated in both India and Chile, with support from partner scientists Dr. Keith Pardee of the University of Toronto, Canada, and Dr. Fernán Federici of the Pontificia Universidad Católica de Chile. Team members from IISER Pune included Tanvi Kale and Rudvi Pednekar, who were instrumental in optimizing the test conditions.

The test’s projected cost is a fraction of conventional RT-PCR kits, making it an attractive option for mass screening. However, further progress hinges on regulatory approvals and funding. “We’ve exhausted our research grants, but we have the manpower and momentum. We’re now looking for institutional or governmental support to take this to clinical trials,” said Athale.

The team is optimistic about scaling the technology to detect other RNA-based viruses such as Ebola, dengue, and influenza. Field trials are expected to begin soon, aiming to bridge the gap between lab innovation and public health delivery.

As the global health community prepares for future pandemics, the IISER biosensor represents a critical step toward accessible, decentralized diagnostics that don’t sacrifice speed or accuracy. With the right backing, this innovation could revolutionize how infectious diseases are detected  not just in India, but across the developing world.