One of the goals is to develop an injectable protein solution that forms a gel inside the body, which could be used in tissue engineering and drug delivery, but also to make gels that can smooth chemical processes where enzymes are used . The study is published in Nature Communications. “We have developed a completely new method to create a three-dimensional gel from spider silk that can be designed to deliver different functional proteins,” said Anna Rising, head of the research group at the Department of Biosciences and Nutrition, Karolinska Institutet and professor at the Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences. “The proteins in the gel are very close together and the method is so gentle that it can even be used for sensitive proteins.”
Injectable protein
In the future, researchers hope to develop an injectable protein solution that forms a gel inside the body. The ability to design hydrogels with specific functions opens up a range of potential applications. Such a gel could, for example, be used to achieve controlled release of drugs in the body. In the chemical industry, it could be fused with enzymes, a form of protein used to speed up various chemical processes. “In the long term, I think injectable gels can become very useful in regenerative medicine,” said study first author Tina Arndt, a PhD student in Rising’s research group at Karolinska Institutet. “We have a long way to go, but the fact that the protein solution forms a gel quickly at body temperature and that spider silk has been shown to be well tolerated by the body is very promising.” The ability of spiders to spin incredibly strong fibers from a silk protein solution in fractions of a second has sparked interest in the underlying molecular mechanisms. The researchers were particularly interested in the ability of spiders to keep proteins soluble so that they do not aggregate before spinning the spider silk.
Ability to shapeshift
Scientists have previously developed a method to produce valuable proteins that mimics the process a spider uses to produce and store its silk proteins. “We’ve shown before that a particular part of the spider silk protein called the N-terminal domain is produced in large quantities and can keep other proteins soluble, and we can exploit that for medical applications,” Rising said. “We’ve let the bacteria produce that part of the protein that binds to functional proteins, including various drugs and enzymes.” The new study shows that the N-terminal domain also has the ability to change shape and transition into small fibrils that cause the protein solution to turn into a gel if incubated at 37°C. It can also be fused to functional proteins that retain their function in the gel.
