Neil Thomas, professor of medicinal and biological chemistry, and Sara Goodacre, lead researcher in the “SpiderLab” at Nottingham and associate professor of medicine and health sciences, led a team of PhD students to use click chemistry to attach antibiotics to artificially produced spider silk that has been synthesized by E.coli to be used in drug delivery, regenerative medicine and wound healing.
Silk proteins had to be created in a bacterium where amino acids in proteins were not normally found. The amino acid had an azide group that is used in click chemistry reactions that only happen at that position in the protein.
Chosen molecules, like antibiotics or fluorescent dyes, can be attached to soluble silk protein. The research team discovered that when the silk fibers are coated in the antibiotic levofloxacin, the antibacterial properties are held on to for at least five days.
“Our technique allows the rapid generation of biocompatible, mono or multi-functionalized silk structures for use in a wide range of applications. These will be particularly useful in the fields of tissue engineering and biomedicine,” said Thomas.
Spider silk has strong, biocompatible and biodegradable properties and is a protein-based material that does not have any allergens or cause immune or inflammatory reactions. The research team developed a way to have the artificial spider silk have the same properties while being a replacement for the cellular matrix that human cells create and accelerate the growth of new cells while slowly releasing antibiotics.
“There is the possibility of using the silk in advanced dressings for the treatment of slow-healing wounds such as diabetic ulcers. Using our technique, infection could be prevented over weeks or months by the controlled release of antibiotics. At the same time tissue regeneration is accelerated by silk fibers functioning as a temporary scaffold before being biodegraded,” said Thomas.
Spider silk is the strongest known natural fiber and has been used in medical applications for centuries. It was known to ease healing and connect the skin. It was also believed that spider silk had antiseptic properties and was effective in clotting blood because of its high vitamin K content. Greek and Roman soldiers used to ball up spider webs and put them in open wounds to stop bleeding.
Thomas and Goodacre met at a University of Nottingham meeting five years ago when Goodacre showed the audience a picture of spider silk and told them that she wanted to figure out how it works and recreate it. Thomas approached her and said that he thought his research team could create the synthetic spider silk with added, useful compounds.
The research was funded by Biotechnology and Biological Science Research Council and was published in the online Advanced Materials journal.