|Silkworms may provide a novel way to store vaccines according to
researchers at Tufts University in Medford, Massachusetts.
Preventable infections kill millions of children in poor countries,
partly because reliable refrigeration for vaccines isn't always
available. Vaccines are refrigerated to slow the rate at which the
biological molecules they contain gradually degrade, largely due to
contact with water.
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
The Tufts University team 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.