The figure shows an example of the mold. Image source: It's not easy for MIT to vaccinate everyone who needs the vaccine. Many vaccines require refrigeration, making it difficult to transport them to remote areas lacking infrastructure. A study published in Nature Biotechnology on the 24th proposed a solution. Scientists at the Massachusetts Institute of Technology in the United States have successfully developed a mobile vaccine printer that can produce hundreds of doses of vaccine in a day. The printer can produce heat stable COVID-19 RNA vaccine, and the immune response of this vaccine in mice is equivalent to that of RNA vaccine injected. This printer can be placed on a desktop and uses hundreds of microneedles containing vaccines to produce patches that attach to the skin, allowing the vaccine to dissolve without traditional injections. Once printed, vaccine patches can be stored at room temperature for several months. The "ink" used by researchers to print microneedles contains RNA vaccine molecules encapsulated in lipid nanoparticles, which helps them remain stable for a long time, even when stored at room temperature or higher. Researchers have found that the 50/50 combination of polyvinyl pyrrolidone and polyvinyl alcohol is the best combination with stiffness and stability. In order to test the long-term stability of the vaccine, researchers first created this RNA ink containing fluorescein protein. They stored the obtained microneedle patches at 4 ℃ or 25 ℃ (room temperature) for up to 6 months before applying them to mice, while also storing a batch of patches at 37 ℃ for one month. Under all these conditions, the patch did not fail. In contrast, the effectiveness of traditional intramuscular vaccines decreases with prolonged storage time at room temperature. Researchers say this work is particularly exciting as it achieves the goal of producing vaccines on demand. Due to the possibility of expanding vaccine production scale and improving stability under high temperatures, mobile vaccine printers can promote widespread access to RNA vaccines. (New News Agency)