Silk Technology Stabilizes Vaccines and Antibiotics

A new silk-based stabilizer could keep some vaccines and antibiotics stable up to temperatures of 60 °C, potentially eliminating the need to keep them refrigerated.

Researchers at Tufts University School of Engineering (Medford, MA, USA) have developed self-standing silk protein biomaterial matrices that essentially wrap up the live bioactive molecules present in antibiotics and vaccines, protecting the essential bioactive elements, and so can greatly extend the shelf life of the medication. Silk is used because it is a protein polymer with a chemistry, structure, and assembly that can generate a unique environment for the stabilization of bioactive molecules, even at temperatures up to 60 °C, over more than 6 months, which could save billions of dollars every year and increase accessibility to third world populations.

To test the silk stabilizers, the researchers stored the measles, mumps, and rubella (MMR) vaccines for six months at the recommended 4 °C, as well as at 25, 37, and 44° C. The encapsulation in the new silk films maintained the potency with minimal loss over time and enhanced stability, even at very high storage temperatures. Similarly, antibiotics entrapped in silk films maintained near optimal activity even at temperatures as high as 60 °C. In addition, the researchers found that these silk films had the added benefit of protecting one antibiotic against the detrimental effects of light exposure. The study was published on July 9, 2012, in the Proceedings of the National Academy of Sciences of the USA (PNAS).

“We have already begun trying to broaden the impact of what we're doing to apply to all vaccines,” said lead author David Kaplan, PhD, of the department of biomedical engineering. “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.”

Vaccines and antibiotics often need to be refrigerated to prevent alteration of their chemical structures; such alteration can result in less potent or ineffective medications. The need for a cold chain has long been a problem for health care providers, aid organizations, scientists, and pharmaceutical companies, especially in settings where electricity is limited, and failures in the chain result in the loss of nearly half of all global vaccines.

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Tufts University School of Engineering