Researchers at Tufts University School of Engineering have discovered a way to maintain the potency of vaccines and other drugs that otherwise require refrigeration for months and possibly years at temperatures above 110 degrees F, by stabilizing them in a silk protein made from silkworm cocoons.
“Silk protein has a unique structure and chemistry that makes it strong, resistant to moisture, stable at extreme temperatures, and biocompatible, all of which make it very useful for stabilizing antibiotics, vaccines and other drugs,” says David Kaplan, leader of the team.
The trick happens at the molecular level. Silk protein fibroin is composed of interlocked crystalline sheets with numerous tiny hydrophobic pockets. The pockets trap and immobilize bioactive molecules, protecting them for the decompositional effect of water and preventing them from unraveling. It’s like enveloping a fragile material in what’s being called “nanoscale Bubble Wrap”.
It is currently necessary to keep bioactive drugs refrigerated all the way from manufacture to use, wherever that may be on the globe. Health experts estimate that nearly half of all global vaccines are lost due to breakdowns in the “cold chain”. The potential for off-infrastructure healthcare, including in war and disaster zones where electricity is unavailable, is enormous.