Silk Technology Preserves Vaccines and Antibiotics Without Refrigeration
Vaccines and other drugs often need to be refrigerated to last, but that can be an obstacle for getting drugs to underdeveloped areas that may need them. Now, researchers at Tufts University discovered that adding a protein made from silkworm cocoons helps maintain the potency of vaccines and other drugs for months and possibly years at temperatures above 110 degrees Fahrenheit.
"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. The fact that we can also make silk into microneedles to deliver a vaccine is an enormous added advantage that can potentially provide a lot of useful solutions to stabilization, distribution and delivery," said David L. Kaplan, who has been studying silk for two decades.
Like Us on Facebook
Kaplan and his team found that silk proteins stabilized preserved the efficacy of the measles, mumps and rubella vaccine (MMR), as well as penicillin and tetracycline, at a wide range of temperatures (at least up to 60 degrees C or 140 F) significantly better than other options such as collagen encapsulants, dried powders and solutions.
The key to the silk solution is the structure of the protein, which forms interlocking sheets of crystals that trap medicine molecules in small pockets, protecting them from water, which can start them decomposing. The pockets also held the molecules that maintain their form without unfolding over time, sort of like microscopic bubble wrap.
According to the paper's first author, Jeney Zhang, who is pursuing a Tufts doctorate in chemical and biological engineering, silk stabilization has "the potential to significantly change the way we store and deliver pharmaceuticals, especially in the developing world."
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, reports Pop Tech.
Measles is one of the leading killers of children worldwide, and without refrigeration, the MMR vaccine quickly becomes impotent. But after six months of storage in freeze-dried silk films at body temperature and at 113 degrees Fahrenheit, the researchers found that all components of the vaccine retained approximately 85 percent of their initial potency.
Tetracycline and penicillin treated with the silk protein also showed remarkably high activity retained after weeks without refrigeration. Tetracycline without the silk protein boost loses 100 percent of its efficacy after just two weeks of storage without refrigeration. And penicillin loses all active ingredients within 24 hours.
So far, according to co-author Bruce Panilaitis, the researchers haven't found any pharmaceutical that they have been unable to stabilize. This could be a "universal storage and handling system."
© 2012 iScience Times All rights reserved. Do not reproduce without permission.