“We have developed a completely new method to create a three-dimensional spider silk gel that can be designed to deliver different functional proteins,” says Anna Rising, head of the research group at the Department of Biosciences and Nutrition, Karolinska Institutet (KI) and professor in the Department of Anatomy, Physiology and Biochemistry of 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.” Injectable protein solution 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,” says study first author Tina Arndt, a PhD student in Anna 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.” It imitates the spinning of spider silk 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 at KI and SLU were particularly interested in the ability of spiders to keep proteins soluble so that they do not aggregate before spinning the spider silk. They have previously developed a method to produce 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 exploit this for medical applications,” says Anna Rising. “We’ve let the bacteria produce that part of the protein that binds to functional proteins, including various drugs and enzymes.” It turns into a gel The new study shows that the N-terminal region 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 in the gel. The research was funded by the European Research Council (ERC), the Center for Innovative Medicine (CIMED) at Karolinska Institutet and Region Stockholm, the Strategic Research Area of Stem Cells and Regenerative Medicine at Karolinska Institutet, the Swedish Research Council, the European Regional Development Fund and the Novo Nordisk Foundation. The study was also conducted using the Biomedicum Imaging Core (BIC) facility at Karolinska Institutet. The researchers declare no conflicts of interest. Story source: Material provided by Karolinska Institutet. Note: Content can be edited for style and length.
