At seven times the tough­ness of Kevlar, a silk pro­duced by the Caerostris dar­wini spider of Mada­gascar is more robust than any other material—synthetic or nat­ural. Most spider silks are about two times tougher than Kevlar, and have long been con­sid­ered an intriguing alter­na­tive for bul­let­proof vests and other pro­tec­tive gear. There’s only one problem: pro­ducing spider silk on demand is a tricky task.

Chem­ical engi­neering stu­dents Robert Jones, Thomas Khoury, and Richard Salvucci spent the last semester of their North­eastern under­grad­uate careers devel­oping a set of solu­tions that could make C. dar­wini silk fibers a viable option for industrial-​​scale man­u­fac­turing. The team’s project won first place at the New Eng­land Bio­engi­neering Con­fer­ence, where they com­peted with hun­dreds of stu­dents from dozens of schools including Cor­nell and Boston University.

The cap­stone stu­dents col­lab­o­rated with Tufts Uni­ver­sity pro­fessor and spider silk expert David Kaplan to engi­neer a the­o­ret­ical method for pro­ducing the silk in bac­te­rial cells at cur­rently unmatched con­cen­tra­tions. Pre­vi­ously, researchers have man­aged to force bac­teria like Escherichia coli to pro­duce silk, but only in small amounts.

The silk gene sequence is large and highly repet­i­tive and cells have trouble repli­cating pro­tein from it, said Jones, who focused pri­marily on the bio­log­ical side of the project. So the young researchers decided to build their model using a genet­i­cally mod­i­fied E. coli strain that more effec­tively deals with the repet­i­tive silk protein.

Photo via Thinkstock.

They incor­po­rated other muta­tions into their hypo­thet­ical E. coli strain to increase its effi­ciency and pro­tein pro­duc­tivity. But the pro­teins pro­duced by these bac­teria do not rep­re­sent the per­fectly spun fibers of spider silk we’re used to seeing, which pre­sented another bar­rier to industrial-​​scale pro­duc­tion. Salvucci tackled this part of the project, designing a system to spin the pro­tein into fibers and col­lect them on giant spools like any fiber used in the tex­tile industry.

The trio of stu­dents chose to form their fibers using microflu­idics; the fibers were only 40 microns thick (less than half the thick­ness of a human hair). “We’re mim­ic­king the bio­log­ical events that actu­ally occur within the spider,” said Salvucci.

The so-​​called Exo-​​Spinner Col­lec­tion system incor­po­rates 10 sets of 15,000 microflu­idic devices, enabling it to pro­duce and col­lect 150,000 fibers at a time. At this rate, the stu­dents esti­mate they could make 100 kilo­grams of spider silk per day, enough to pro­duce 50 bul­let­proof vests.

With his sights set on busi­ness school, Khoury focused on the eco­nomics of the project. Based on a series of assump­tions drawn from the cur­rent market, Khoury fore­casted a demand of 1.5 bil­lion vests per year and believes they could break in at one per­cent of the market. While the spider silk vest would be sig­nif­i­cantly more costly than the stan­dard option, the stu­dents say it would also be lighter, more com­fort­able, and more versatile.

They also believe that industrial-​​scale spider silk pro­duc­tion could rev­o­lu­tionize the tex­tile industry as a whole, pro­viding a novel mate­rial for prod­ucts ranging from seat­belts to sail­boats. “You’re only lim­ited by your imag­i­na­tion,” said Khoury.