A tiny skin patch carrying an mRNA vaccine may one day help overcome one of the greatest obstacles to modern immunisation: the need for costly ultra-cold storage.

Researchers from RMIT University, the Massachusetts Institute of Technology (MIT) and Harvard Medical School have identified how to better protect the delicate particles that carry mRNA when vaccines are dried into dissolvable microneedle patches. Their findings, published in the journal Advanced Functional Materials, could help make future vaccines easier to transport and use, particularly in remote and low-resource communities.

Unlike traditional injections, microneedle patches contain hundreds of tiny, almost painless projections that dissolve into the skin. The vaccine's mRNA, which is a short set of instructions that helps the body's cells learn to identify and combat a virus, is enclosed in tiny fat-based bubbles called lipid nanoparticles that protect the delicate genetic material until it gets to the cells.

The problem has always been that these nanoparticles are extremely sensitive. During months of laboratory work, researchers closely monitored the nanoparticles using advanced imaging and X-ray techniques before drying, while they dried, and after they were mixed with water again. Those observations revealed which patch formulations best preserved the particles' structure and biological activity after the stressful drying process.

Lead author Dr Brendan Dyett of RMIT said the findings move scientists closer to vaccines that are simpler 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 study found that the design of the lipid nanoparticles and the amount of polymer in the dissolvable patch influenced how well the vaccine stayed intact when dried and how effectively it worked again when rehydrated. The work builds on earlier MIT research showing that printed mRNA vaccine patches could remain stable at room temperature but now explains why some formulations perform better than others.

The breakthrough could have implications far beyond the laboratory. According to the World Health Organization (WHO) and UNICEF, 14.3 million children received no vaccines in 2024, with weak cold-chain infrastructure remaining a major barrier in many parts of the world. Scientists believe room-temperature vaccine patches could reduce dependence on refrigerated transport, making immunisation campaigns faster, cheaper and more resilient during outbreaks and humanitarian crises.

Lead researcher Distinguished Professor Calum Drummond AO said the ultimate goal extends beyond scientific innovation.

“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 effective, practical technologies for the communities that need them most.”

While further testing is needed before such patches reach clinics, the study provides an important scientific roadmap for developing mRNA vaccines that are not only effective but also practical enough to reach the people who need them most.