Who would have guessed that something as fine as silk could be so sturdy? That's what a team of scientists are learning as they've proven that silk, reduced down to a thin film wrapped around antibiotics and vaccines can help extend their shelf life. It's a development that could be critical to bringing key medicines to the Third World.
Many vaccines and antibiotics need to be refrigerated in order to maintain their efficacy. Keeping these medications cold dramatically adds to the cost of drugs — in some cases up to 80% due to transportation and storage (called the cold chain system). Even still, it's estimated that up to half of these delicate drugs are lost during the process.
A team led by Dr. David Kaplan, Ph.D, from Tufts University was successful in creating a silk fibroin film which is a protein polymer refined from domesticated silkworms. When used as a liquid, the protein polymer essentially wraps up the live bioactive molecules in antibiotics and vaccines.
The team found the unique chemistry, structure and process of mixing the silk protein polymer with the drugs to be ideal in creating a perfect protective nano-coating that protects not only from heat, but light as well. Researchers were able to successfully preserve the measles, mumps and rubella vaccine (MMR), tetracycline and penicillin at temperatures of 113 degrees Fahrenheit for six months in lab conditions.
The team expects they may well be able to store some drugs and vaccines at temperatures up to 130 degrees Fahrenheit, and possibly store others for much longer than six months while still remaining stable and effective. Their next step is to test in real world conditions.
When proven in the field it could have a massive worldwide impact. Eliminating the need for refrigeration will not only make drug prices drop — a boon to those who desperately need them in the developing world, it will also allow access for areas that may have no electricity at all.
Now that the years-in-the making breakthrough has been made, Dr. Kaplan is looking toward the future. In a release provided by the National Institute of Health he said:
"New studies are already under way. We have already begun trying to broaden the impact of what we're doing to apply to all vaccines. Based on what we've seen with other proteins, peptides, and enzymes, there's no reason to believe that this wouldn't be universal. This could potentially eliminate the need for a cold-chain system, greatly decreasing costs and enabling more widespread availability of these life-saving drugs."
The research was led by grantees of NIH's National Institute of Biomedical Imaging and Bioengineering (NIBIB), David Kaplan, Ph.D., and Jeney Zhang, Ph.D. candidate, at Tufts University School of Engineering in Medford, Mass. The National Eye Institute and the National Institute of Dental and Craniofacial Research at NIH also contributed to this research. The researchers reported on their findings in the Proceedings of the National Academy of Sciences on July 9, 2012.