Engineers want to use peptides—small proteins that carry out essential tasks in our cells—to construct bioelectronic devices.
These genetically engineered peptides can assemble into nanowires atop 2D, solid surfaces that are just a single layer of atoms thick.
“Nature must constantly make materials to do many of the same tasks we seek.”
These nanowire assemblages are critical because the peptides relay information across the bio/nano interface through molecular recognition—the same principles that underlie biochemical interactions such as an antibody binding to its specific antigen or protein binding to DNA.
Since this communication is two-way, with peptides understanding the “language” of technology and vice versa, their approach essentially enables a coherent bioelectronic interface.
“Bridging this divide would be the key to building the genetically engineered biomolecular solid-state devices of the future,” says Mehmet Sarikaya, a professor of materials science, engineering, and oral health sciences at the University of Washington.
His team studies how to co-opt the chemistry of life to synthesize materials with technologically significant physical, electronic and photonic properties. To Sarikaya, the biochemical “language” of life is a logical emulation.
“Nature must constantly make materials to do many of the same tasks we seek,” he says.
Finding the perfect peptide
They want to find genetically engineered peptides with specific chemical and structural properties. They sought out a peptide that could interact with materials such as gold, titanium, and even a mineral in bone and teeth. These could all form the basis of future biomedical and electro-optical devices.
Their ideal peptide should also change the physical properties of synthetic materials and respond to that change. That way, it would transmit “information” from the synthetic material to other biomolecules—bridging the chemical divide between biology and technology.
In exploring the properties of 80 genetically selected peptides—which are not found in nature but have the same chemical components of all proteins—they discovered that one, GrBP5, showed promising interactions with the semimetal graphene.
They then tested GrBP5’s interactions with several 2D nanomaterials which, Sarikaya says, “could serve as the metals or semiconductors of the future.”
“We needed to know the specific molecular interactions between this peptide and these inorganic solid surfaces,” he adds.
Their experiments, detailed in a paper in Scientific Reports, show that GrBP5 spontaneously organized into ordered nanowire patterns on graphene. With a few mutations, GrBP5 also altered the electrical conductivity of a graphene-based device, the first step toward transmitting electrical information from graphene to cells via peptides.
In parallel, Sarikaya’s team modified GrBP5 to produce similar results on a semiconductor material—molybdenum disulfide—by converting a chemical signal to an optical signal. They also computationally predicted how different arrangements of GrBP5 nanowires would affect the electrical conduction or optical signal of each material, showing additional potential within GrBP5’s physical properties.
“In a way, we’re at the flood gates,” says Sarikaya. “Now we need to explore the basic properties of this bridge and how we can modify it to permit the flow of ‘information’ from electronic and photonic devices to biological systems.”
The University of Washington, National Science Foundation, the National Institutes of Health, and the Japan Science and Technology Agency funded the work. Lead author of the paper is former University of Washington postdoctoral researcher Yuhei Hayamizu, who is now an associate professor at the Tokyo Institute of Technology.
Source: University of Washington