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Winter 2009 Seminar Series
Friday, February 27, at 3:30 p.m.
Room 264 MacQuigg Labs
Markus Buehler
Laboratory for Atomistic and Molecular Mechanics,
Department of Civil and Environmental Engineering,
Massachusetts Institute of Technology,
Cambridge, MA
Deformation and Failure of Biological Protein Materials
Abstract
Biological protein materials (BPMs) feature intriguing hierarchical structures, ranging through the atomistic, molecular to macroscopic scales to form functional biological tissues as diverse as spider silk, tendon, bone, skin, hair or cells. Here I will present theoretical and computational studies, focused on how BPMs deform and fail due to extreme mechanical conditions, disease and injuries. Based on a multi-scale atomistic simulation approach that explicitly considers the architecture of proteins including the details of chemical bonding, we have developed predictive models of the deformation and fracture behavior of protein materials, validated through quantitative comparison with experimental results. The use of "model materials" and supercomputing approaches enables us to extract general physical concepts that control the properties of BPMs, in order to understand their behavior in the stability-instability-robustness domain. I will present a systematic investigation of several major classes of protein materials, including cellular alpha-helix rich protein networks, beta-sheet structures, as well as collagenous tissues.
An overarching aspect that controls the properties of protein materials is the behavior of clusters of H-bonds, a type of biology's cement that provides structure to a variety of protein materials. I will discuss deformation mechanisms and the strength limit of H-bonds, confinement effects in protein nanostructures and associated evolutionary driving forces, as well as the role of material hierarchies. These studies are enabled through a combination of large-scale atomistic simulation and theoretical modeling based on the Hierarchical Bell Model. Case studies are presented that illustrate how structural changes can lead to the formation of structural flaws, applications in genetic diseases, as well as in the role of mechanical driving forces that lead to the onset of instabilities.
The understanding of how molecular structure and material properties are linked may lead to a paradigm shift in the understanding of basic mechanisms in the behavior of biological systems, in the understanding of injuries and genetic diseases, as well as in disease diagnosis and treatment. The transfer towards the design of novel nanostructures may lead to new multifunctional and mechanically active, tunable and changeable materials.
Bio
 |
Dr. Markus Buehler |
After obtaining his undergraduate education at the University of Stuttgart, Germany in Chemical and Process Engineering, Prof. Markus Buehler received his M.S. degree in Engineering Mechanics from Michigan Technological University, USA, in 2001. From 2001 to 2004 he worked at the Max Planck Institute for Metals Research in Stuttgart, Germany as a research assistant, from where he also received his Ph.D. in Chemistry. From 2004 to 2005, Prof. Buehler held an appointment as the Director of Multiscale Modeling and Software Integration at the Materials and Process Simulation Center at the California Institute of Technology, overseeing multiscale method development and applications in modeling of small-scale materials phenomena. In 2005, he joined MIT for an appointment as a Postdoctoral Associate, and in 2006 he became a faculty member in MIT's Department of Civil and Environmental Engineering. Prof. Buehler founded MIT's Laboratory for Atomistic and Molecular Mechanics.
His research has pioneered the multi-scale analysis of deformation and fracture of biological protein materials, with a particular focus on collagenous tissues, bone, spider silk, amyloids, as well as the mechanics of the cell's cytoskeleton. His main interest is the elucidation of materials science paradigms for protein materials, with particular focus on fracture and deformation and the development of biomimetic materials and structures, an effort that falls in the realm of materiomics. His work is published in a variety of leading journals including the Biophysical Journal, Physical Review Letters, Materials Today, Proceedings of the National Academy of Sciences USA, Nature Materials, Nature, as well as in MIT Technology Review. Prof. Buehler has received several awards, including the 2004 Materials Research Society Gold Graduate Student award, the 2007 National Science Foundation CAREER award, the 2008 U.S. Air Force Young Investigator Award, the 2008 Navy Young Investigator Award, and the 2008 DARPA Young Faculty Award. He is a participant and speaker at the Frontiers of Engineering Symposium of the U.S. National Academy of Engineering, and has given several keynote lectures at international conferences. He currently holds the Esther and Harold E. Edgerton Career Development Professorship at MIT.
Please join our speaker for light refreshments in 479 Watts Hall following the talk.
