New drying technique stabilizes vital vaccines at room temperature

A significant challenge in global healthcare and biotechnology is the "cold chain"-the network of refrigerated storage and transport required to keep protein-based drugs, vaccines, and diagnostic tests from degrading. This reliance on constant low temperatures is expensive and energy-intensive, and often fails in regions lacking reliable electricity, leading to high wastage rates. Now, a team from the University of Oxford's Department of Engineering Science has validated a promising alternative: a simple, room-temperature drying technique that locks functional proteins into a stable, sugar-based "glass."

In their paper published in Engineering, the researchers, led by Professor Zhanfeng Cui, detailed the success of matrix-assisted room-temperature (MART) drying. The process involves mixing functional proteins with protective sugars (trehalose and dextran) and drying the solution onto a biocompatible cellulose fiber matrix at room temperature or an evaluated temperature (~30 °C). The drying process can be performed either with circulating dry air (MART-DA) or under a vacuum (MART-V), completely avoiding the freezing step that often damages sensitive biomolecules.

The key to the method lies in the formation of microscopic "capillary bridges" between the cellulose fibers. As the sugar solution dries, it forms thin films that gently encapsulate the proteins, preserving their three-dimensional structure and biological function. This mechanism was successfully demonstrated across four distinct, temperature-sensitive targets: the enzyme lactate dehydrogenase (LDH), the cell-growth-promoting fibroblast growth factor 2 (FGF-2), and the complex enzyme mixture (reverse transcriptase and Bst 2.0 polymerase) used in COVID-19 RT-LAMP diagnostic tests.

MART-dried LDH retained over 90% of its activity after six months of storage at 25 °C, matching the performance of traditional frozen storage. Critically, FGF-2 dried using this method remained biologically active; when reconstituted after a week at 40 °C, it promoted stem cell proliferation as effectively as −80 °C-stored FGF-2. Furthermore, the complete RT-LAMP reagent set for COVID-19 detection was successfully thermostabilized, remaining sensitive enough to detect viral RNA after being stored at 40 °C for a week.

MART drying offers several profound advantages over conventional freeze-drying (lyophilization). It reduces processing time from a day or more to as little as three hours (using vacuum), consumes significantly less energy, and requires no expensive specialized equipment. The use of a soft cellulose matrix also eliminates the brittleness issues associated with previous glass-fiber prototypes, making it safer and more adaptable for direct applications, such as embedding growth factors into wound dressings.

By enabling the long-term, room-temperature storage of vital biologics, this research paves the way for expanding access to advanced diagnostics and treatments in low-resource environments, simplifying supply chains, and reducing the global carbon footprint of the biopharmaceutical industry.