Dry Vaccine Patches Inch Closer to Skipping the Cold Chain

New research could help make future mRNA vaccines easier to store and distribute. The study, a collaboration between RMIT University, the Massachusetts Institute of Technology, and Harvard Medical School, identified conditions that help protect the particles carrying mRNA when they are dried into dissolvable microneedle patches, offering practical guidance for future patch design.

Published in Advanced Functional Materials, the study examines what happens to the fragile particles used to carry mRNA when they are dried into the dissolvable material used in these patches, which deliver vaccine into the skin through hundreds of tiny tips as an alternative to traditional injections. Reducing the need for cold-chain logistics could remove one barrier to vaccine delivery, particularly in lower-resource settings.

The paper builds on earlier MIT-led research showing that patches could be printed and stored at room temperature using a model mRNA system. This new study goes further, explaining why some dry patch formulations perform better than others by drawing on RMIT's materials characterization expertise, MIT's work in microneedle and mRNA delivery technologies, and Harvard Medical School's expertise in virology and immunology.

Lead author Brendan Dyett said the findings represent an important step toward making vaccines easier and cheaper to distribute. "Many mRNA vaccines need to be stored at very low temperatures, adding cost and complexity to transport and delivery," Dyett said. "Our study helps explain how the particles that carry mRNA respond to drying and rehydration, which is an important step towards designing future vaccine patches that are more stable and practical to distribute." 

The team used advanced imaging and X-ray techniques to study the mRNA-carrying particles before drying, during drying, and after rehydration, allowing them to observe how the particles changed throughout the process and identify which formulation conditions best preserved their structure and biological activity. The study found that both nanoparticle design and the amount of polymer used in the patch material influenced how well the particles survived drying and re-dissolving, providing practical guidance for future dry mRNA vaccines and therapies.

Lead research Calum Drummond said the work could help pave the way for mRNA vaccines and treatments that are more practical to use in a wider range of settings. "This research is helping build the foundation for microneedle patches that could make advanced vaccines and therapies simpler to use and easier to access," Drummond said. "The long-term goal is to support technologies that are not only effective, but practical for the places and communities that need them most."

Next steps include further optimizing the nanoparticle and patch formulations, testing how the design translates to immune responses, and exploring whether similar approaches could apply to other mRNA medicines.