Researchers Turn Silk Proteins and Graphene Into Flexible Transistors

They say you can't make a silk purse out of a sow's ear, but researchers from the Pacific Northwest National Laboratory (PNNL), University of Washington, Lawrence Berkeley National Laboratory, Stanford University, the University of California at Berkeley, North Carolina State University, and Xiamen University have succeeded in turning silk and graphene into working flexible circuits suitable for wearables, implantable health devices, and more.

"These results provide a reproducible method for silk protein self-assembly that is essential for designing and fabricating silk-based electronics," explains Chenyang Shi, lead author of the study, of the team's work on silk-and-graphene circuitry. "It's important to note that this system is non-toxic and water-based, which is crucial for biocompatibility."

"There's been a lot of research using silk as a way of modulating electronic signals, but because silk proteins are naturally disordered, there’s only so much control that's been possible," adds James De Yoreo, a Battelle Fellow at PNNL with a dual appointment as a Professor of Materials Science and Engineering and of Chemistry at the University of Washington. "So, with our experience in controlling material growth on surfaces, we thought 'what if we can make a better interface?'"

The team's work focuses on a combination of silk proteins and graphene, a single-atom-thick layer of carbon. Using these materials, the researchers assembled a two-dimensional layer of proteins that exhibits field effects — forming a working, miniature, flexible transistor. The team believes the same approach could also be used to form a silk-based memristor — a device that acts like a resistor with memory.

The researchers' work has been published under open-access terms in the journal Science Advances.

Main article image courtesy of Mike Perkins/Pacific Northwest National Laboratory.