Dr. David Needham and graduate student Deborah Rickard
Duke University researchers developed a glassification technique that could bring about protein-based drugs that are cheaper to make and easier to deliver than current techniques which render proteins into freeze dried powders to preserve them.
Duke engineer and chemist David Needham describes this glassification process as “molecular water surgery” because it removes virtually all the water from around a dissolved protein by almost magically pulling the water into a second solvent.
“It’s like a sponge sucking water off a counter,” said Needham, a professor of mechanical engineering and materials science at Duke’s Pratt School of Engineering, who has formed a company called Biogyali (“gyali” means glass in Greek) to develop the innovation. That firm has also applied to patent the idea of turning proteins into tiny glass beads at room temperature for drug delivery systems.
Preliminary evaluations by his senior scientist David Gaul and a team of undergraduate students showed that four test proteins undergoing such procedures retained all or most of their original activity when water was restored. His group has received about $1 million from the National Institutes of Health grants for the research.
Having devised a way to turn proteins into glassy microbeads measuring only about 26 millionths of a meter in diameter, Needham hopes those can be directly injected into the body for use as “biologic” drugs. These microbeads might also be packaged for slow time-release by surrounding them with a polymer that would biodegrade over time, though how to do that has not been resolved yet, he added.
Their discovery of protein glassification grew out of a basic exploration of a general question: What can dissolve in what? Needham’s research group found, for example, that air and the organic liquid chloroform will both dissolve in water at about the same rate. It also found that water will dissolve in decanol, a substance it cannot even mix with in large quantities.
Proteins are currently dried into clumpy, irregular powders by several industrial processes — usually freeze-drying — to protect them from such microbe damage. Drying also avoids the chemical breakdowns that can also occur when proteins are kept in solution. “But in the freeze-drying process itself, some very sensitive biologic drugs can also get damaged,” Needham said.
Freeze-drying proteins into solids is also slower and more expensive than glassifying them, he added. And the resulting “flaky” powder is harder to handle than glassified beads. Glassification “is a fast process,” said Gaul, a senior research scientist in Needham’s lab. Unlike freeze-drying, “we can dry particles within minutes, if not seconds, and don’t need any specialized equipment.”
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