he boxes arrive from Japan, full of what look like packing peanuts. But these white oblong shapes aren’t there just to protect some other cargo. These are silkworm cocoons. Snip them open, throw out the brownish grub inside, boil down the casing, and you are left with a near-magical material.
David Kaplan has used silk to make vaccines and antibody drugs that don’t need to be refrigerated. And now, in a paper published Monday in the Proceedings of the National Academy of Sciences, the Tufts University bioengineer and his colleagues have shown that silk could be used to preserve blood samples at room, or even body temperatures.
“We’re still a ways away from having a viable technology that can be brought to the patient’s doorstep,” said Roger Peck, a diagnostics specialist at the global health nonprofit PATH. But, he noted, the technology could make diagnostic tests more accessible to rural communities — and potentially more accurate.
Often, a diagnosis relies on identifying certain proteins in the blood that signal the presence of a disease. But once blood is removed from the body, those proteins can be hard to find and identify. Sometimes it’s because enzymes in the blood devour them; other times, heat deforms them.
Those processes can be slowed down with refrigeration, but refrigeration is hard to come by when in rural settings without reliable electricity — and coolers will only stay cool for a little over a day.
The most common solution is to collect what’s called a dried blood spot. This involves taking a pinprick of blood and drying it onto a special bit of cardboard. Yet once these spots are back in the lab, they often don’t contain enough blood for analysis. And there are conditions in which they aren’t able to preserve certain molecules, and most labs prefer to refrigerate them.
“With anything like high humidity or high temperature, the proteins are not protected by any sort of coating or physical entrapment,” explained Jonathan Kluge, a coauthor on the paper. With silk, though, that isn’t as much of an issue.
Kluge used to work at Tufts and is now director of R&D at Vaxess Technologies, a company that spun out of Kaplan’s lab. Back when he was still in academia, he and his lab mates created both a silk powder and a silk solution. They mixed these substances with blood, let the mixtures dry, and found that even at high temperatures, the silk-preserved blood still yielded almost all of the proteins more reliably than either frozen blood samples or dried blood spots.
So far, this technology has only been tested in the lab. Dr. Madhukar Pai, a tuberculosis specialist at McGill University, who has done research on diagnostic tests, said the real evaluation will come in the field, “where high temperatures, humidity, dust, and transportation delays are the norm, rather than the exception.”
Silk-based blood diagnostics are also a far way from commercialization. Vaxess has licensed some technology from Kaplan’s lab for making therapeutics stabilized by silk, but so far they have not struck a deal over the latest blood research.
Such a deal could come soon. “It wouldn’t take a lot to commercialize this,” said Kaplan, a scientific advisor to Vaxess. “It makes sense for Vaxess based on their scope of their commercialization interests.”