Sinan Keten, PhD
A materials-by-design approach to discovering bioinspired membranes
Civil & Environmental Engineering and Mechanical Engineering
Folding and self-assembly of proteins into transmembrane channels with well-described interior chemistry and pore size is foundational to nature’s solutions to chemical separation. Achieving flux and selectivity similar to those seen in biological systems remains as a grand challenge that must be overcome to address ever increasing societal needs for clean water, carbon capture and energy storage. In pursuit of an accelerated pathway towards discovering novel bioinspired membranes through computer simulations, this talk will summarize recent advances in predicting the assembly, mechanics, and transport capabilities of hybrid nanocomposites that blend the best aspects of biomolecules and engineering polymers. I will focus on our recent advances in describing the physical behavior of polymer conjugated cyclic peptide nanotubes (pc-CPNs) that self-assemble into biomimetic artificial nanochannels in block copolymer membranes. pc-CPNs offer precise control of the pore diameter as well as interior polarity through nonstandard mutations presented in the amino acid sequence. I will discuss how the entropic penalty of polymer conjugation can be a useful tool to direct the self-assembly of functionalized CPs towards a defined stacking sequence. These findings will culminate in a concept model that illustrates how ring shaped molecules could form nanotubes with spatially tunable interiors, and thereby achieve potentially unforeseen transport properties. Most interestingly, I will present recent findings that explain why kinetic traps can hamper structural control in some experimental conditions, and offer guidelines on how to overcome them and reach thermodynamically predictable assemblies of mixed nanoblocks by understanding circularity the interplay between chemistry and mechanics. Finally, I will conclude by emphasizing the broad importance of a materials-by-design viewpoint for making new bioinspired materials that capture unique functionalities of protein materials in polymeric systems.
BIO: Sinan Keten is an Assistant Professor of Civil & Environmental Engineering and Mechanical Engineering at Northwestern University. He joined Northwestern University faculty in 2010 after obtaining his Ph.D. in Civil & Environmental Engineering from MIT. His research expertise is on computational materials science and mechanics with an emphasis on biological and bioinspired systems. He has made original contributions to elucidating structure – property relationships in biological materials such as spider’s silk, which is one of the toughest materials known, and nanocellulose, nature’s most abundant structural building block. His most notable contributions have involved theoretical calculations and multi-scale simulations that have explained how biological nanostructured materials achieve strength and toughness through important molecular level size and geometric effects. He has published 40 articles in journals such as Nature Materials, PNAS, and Nano Letters that have been cited in over 1000 scientific articles, and highlighted in mainstream media, Science, and Nature Physics. Dr. Keten currently serves as the principal investigator for federally funded research projects by the National Science Foundation (The Materials Genome Initiative), Office of Naval Research, and Army Research Office. He has given numerous invited lectures and keynotes around the world and has received awards from the Materials Research Society and the American Society of Mechanical Engineers. Dr. Keten is also actively involved in creating new web-based educational tools that facilitate training of students and researchers in mechanics, materials and computational engineering around the world.