Scientists develop gel from spider silk proteins for biomedical applications
Researchers from Karolinska Institutet in Sweden and the Swedish University of Agricultural Sciences have found that spider silk proteins can be fused to biologically active proteins and converted 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 could be used in tissue engineering and for drug delivery, but also to make gels that can streamline chemical processes where enzymes are used. The study is published in Nature Communications.
“We have developed an entirely new method to create a three-dimensional gel from spider silk that can be engineered to deliver different functional proteins,” said Anna Rising, research group leader in the Department of Biosciences and Nutrition, Karolinska Institutet and Professor in the Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences.
“The proteins in the gel are very close to each other and the method is so gentle that it can be used even for sensitive proteins.”
In the future, the 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 possible applications. Such a gel could, for example, be used to obtain 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 a little longer term, I think injectable gels can become very useful in regenerative medicine,” said the study’s first author, Tina Arndt, a doctoral student in Rising’s research group at Karolinska Institutet.
“We have a long way to go, but the fact that the protein solution quickly forms a gel at body temperature and that the spider silk was found to be well tolerated by the body is promising.”
The ability of spiders to weave incredibly strong fibers from a solution of silk proteins in fractions of a second has sparked interest in the underlying molecular mechanisms. The researchers were particularly interested in the spiders’ ability to keep proteins soluble so they don’t clump together before the spider silk is spun.
Scientists have previously developed a method of producing valuable proteins, which mimics the process used by the spider to produce and store its silk proteins.
“We have already shown that a specific part of spider silk protein called the N-terminal domain is produced in large quantities and can keep other proteins soluble, and we can exploit it for medical applications,” said Rising.
“We let the bacteria produce that 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 transform into small fibrils that cause the protein solution to convert into a gel if incubated at 37°C. Moreover, it can be fused to functional proteins which preserve their function in the gel.