Newswise — Researchers at Sweden’s Karolinska Institutet and the Swedish University of Agricultural Sciences have discovered that proteins in spider silk can fuse with biologically active proteins and turn into a gel at body temperature. One of the goals is to develop an injectable protein solution that forms a gel inside the body, which can be used in tissue engineering and for the release of drugs, but also to manufacture gels that can speed up the chemical processes where they use enzymes. 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,” says Anna Rising, research group leader at the Department of Biosciences and Nutrition, Karolinska Institutet (KI ) and professor in the Department of Anatomy, Physiology and Biochemistry at the Swedish University of Agricultural Sciences (SLU). “The proteins in the gel are very close together and the method is so gentle that it can be used even for sensitive proteins.”
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 number of possible applications. This gel could be used, for example, to achieve a 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 slightly longer term, I think injectable gels can be very useful in regenerative medicine,” says the study’s first author, Tina Arndt, a PhD student in Anna Rising’s research group at Karolinska Institutet. “We still have a long way to go, but the fact that the protein solution rapidly forms a gel at body temperature and that spider silk has been shown to be well tolerated by the body is 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 KI and SLU researchers have been particularly interested in the ability of spiders to keep proteins soluble so they don’t clump together before spinning spider silk. They have previously developed a method for producing valuable proteins that mimics the process the spider uses to produce and store its silk proteins.
“We have previously shown that a specific 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 take advantage of this for medical applications,” says Anna Rising. “We have left Bacteria produce this part of the protein bound 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. In addition, it can be fused to functional proteins that retain their function on the gel.
The research was funded by the European Research Council (ERC), the Center for Innovative Medicine (CIMED) at Karolinska Institutet and the Stockholm Region, the Strategic Research Area for Stem Cells and Regenerative Medicine at Karolinska Institutet , the Swedish Research Council, the European Regional Regional. Development Fund and the Novo Nordisk Foundation. The study was also performed using the main facility Biomedicum Imaging Core (BIC) at Karolinska Institutet. The researchers declare no conflicts of interest.