New Scientist – Silkworms may provide a novel way to store vaccines. Preventable infections kill millions of children in poor countries, partly because reliable refrigeration for vaccines isn’t always available.
Fibroin, a protein in silk, forms stable sheets that contain tiny pockets lined with molecules that repel water. You can trap a biological molecule within these pockets by dissolving it with fibroin in water, then drying it to form a film. Tucked away in a pocket, the molecule is protected.
David Kaplan and colleagues at Tufts University in Medford, Massachusetts, made such films with the live measles, mumps and rubella viruses in the MMR vaccine. The films kept the viruses undamaged for six months, even powdered and at temperatures of 45 °C, when regular freeze-dried vaccines degraded rapidly.
Abstract Sensitive biological compounds, such as vaccines and antibiotics, traditionally require a time-dependent “cold chain” to maximize therapeutic activity. This flawed process results in billions of dollars worth of viable drug loss during shipping and storage, and severely limits distribution to developing nations with limited infrastructure. To address these major limitations, we demonstrate self-standing silk protein biomaterial matrices capable of stabilizing labile vaccines and antibiotics, even at temperatures up to 60 °C over more than 6 months. Initial insight into the mechanistic basis for these findings is provided. Importantly, these findings suggest a transformative approach to the cold chain to revolutionize the way many labile therapeutic drugs are stored and utilized throughout the world.