Transforming artificial spider silk into next-generation medical materials

It’s almost time to dust off the Halloween decorations and deck out the house with all sorts of spooky things, including the classic polyester spider webs. Scientists report in ACS Nano Scientists have created their own version of fake spider silk, but this one is made of protein and heals wounds instead of haunting the hallways. The artificial silk was strong enough to be woven into bandages that helped treat joint injuries and skin lesions in mice.

Spider silk is one of the strongest materials on Earth, technically stronger than steel for a material of its size. However, it is difficult to obtain: spiders are too territorial (and cannibalistic) to reproduce them like silkworms, leading scientists to turn to artificial options.

One option is to teach microbes to produce spider silk proteins through genetic engineering, but this has proven difficult because the proteins tend to stick together, reducing the yield of the silk. So Gao and his colleagues wanted to tweak the natural protein sequence to design easy-to-spin, yet stable, spider silk using microbes.

The team first used these microbes to produce silk proteins, also adding additional peptides. The new peptides, following a pattern found in the protein sequence of amyloid polypeptides, helped the artificial silk proteins form an ordered structure when folded and prevented them from sticking together in solution, increasing their yield.

Then, using a set of tiny hollow needles attached to the nozzle of a 3-D printer, the researchers sucked the protein solution into thin strands from the air and wove them together to form a thicker fiber. This configuration acted like a giant artificial spider spinning its web.

They then spun their artificial silk fibers into prototype bandages, which they applied to mice with osteoarthritis (a degenerative joint disease) and chronic wounds caused by diabetes. Drug treatments were easily added to the bandages, and the team found that the modified bandages stimulated wound healing better than traditional bandages.

Compared to a control group with neutral dressings, mice with osteoarthritis showed reduced swelling and repair of tissue structure after 2 weeks of treatment, while diabetic mice with skin lesions treated with a similar dressing showed significant wound healing after 16 days of treatment. The new silk dressings are biocompatible and biodegradable, and the researchers say they hold promise for future applications in medicine.