Keeping vaccines and research samples at the right temperature is a critical challenge, as even brief exposure to unsafe conditions can compromise their safety. At Arizona State University, Associate Professor Chad Borges and his team have developed a new solution to address this issue. Their work has resulted in chemical time-temperature indicators (TTIs) that provide a visual signal if biological materials have been exposed to inappropriate temperatures.
Borges, who works in the School of Molecular Sciences and is affiliated with the Biodesign Institute’s Virginia G. Piper Center for Personalized Diagnostics, explained the unique capability of their innovation. “The novelty of our indicators is that they keep running even at extreme subzero temperatures,” Borges said. “This permits them the unique ability to signal if a vaccine or biospecimen has been exposed to inappropriately warm conditions that could compromise its effectiveness.”
Unlike most commercial indicators that only function down to about -18 C—sufficient for food storage but not for scientific needs—the TTIs created by Borges’ startup CryoVeritas remain active at much lower temperatures, including -37 C or even -67 C as required.
The chemistry behind these indicators uses a permanganate/oxalate reaction that changes from vivid pink to colorless in a predictable manner. This clear shift allows users—including those who are colorblind—to easily determine if temperature limits have been exceeded.
The team spent years refining the reaction so it would be reproducible, accurate, and customizable. The TTIs can be adjusted for different durations and temperature ranges, from -67 C up to 37 C or higher. To achieve colder thresholds, antifreeze salts called perchlorates were added to the solutions.
Biological molecules are often unstable; if their required cold-chain is broken, this can result in wasted resources, failed experiments, or less effective vaccines. The low-cost and easy-to-use TTIs are already being adopted by labs and companies across the country.
CryoVeritas was formed through a partnership between ASU’s Skysong Innovations and General Inception, LLC. The company expects additional funding soon to increase production capacity.
Research on these TTIs was recently published in Chemical Engineering Journal as well as Reaction Chemistry and Engineering by the Royal Society of Chemistry, where it appeared on the cover. Postdoctoral researcher Jorvani Cruz Villarreal was first author on one study; graduate students Emil Ljungberg and Nilojan Jehanathan and undergraduates Milap Owens and Anika Li also contributed.
Arizona State University continues its reputation for innovation; according to U.S. News & World Report, ASU has held the top spot for innovation among colleges for eight consecutive years.
