Special Seminar - Nanomechanics: Opportunities in Tissue Assessment, Regeneration and Mimetics
Date: May 10, 2012
Time: 12:00 PM
Location: Bossone Research Enterprise Center, Room: 709
Speaker(s):
Lin Han, PhD
Post-Doctoral Associate
Department of Materials Science and Engineering
and the Center for Biomedical Engineering
Massachusetts Institute of Technology (MIT)
Details:
Debilitating ailments, such as osteoarthritis, often lead to irreversible degradation and dysfunction of load bearing tissues. Medical applications of nanotechnologyhave yet to advance to significant clinical use in vivo, as there is a knowledge gap between fundamental biological processes that take place at the nanoscale and conventional macroscale diagnostic and therapeutic approaches. Quantification of nanostructural and nanomechanical properties associated with tissue development and pathology holds the key to enable early stage diagnosis of connective tissue diseases as well as to assess and optimize treatment interventions, all at unparalleled resolutions. In my research, new experimental methods for probing nanoscale structure-property relationships were developed, including atomic force microscopy (AFM)-based nanomechanical modalities (compression, shear, adhesion, nanoindentation and dynamic oscillatory loading), high resolution AFM imaging, and uniaxial microcompression. These methods were used to study nanostructure and nanomechanics of the model system of articular cartilage, a hydrated macromolecular composite. We discovered that cartilage tissue function is determined by the assembly andinteractions of its molecular matrix constituents (e.g., aggrecan, collagen and other non-collagenous proteins) at the nanoscale. The ultrastructure and charge density of aggrecan, non-additive aggrecan-aggrecan and aggrecan-collagen interactions, nanoscale flow-induced poroelasticity, salt screening, and the presence of calcium ions are important factors that govern the compression, shear, energy dissipation and integrity of the cartilage fabric. Furthermore, highresolution AFM imaging and force spectroscopy were applied to document the effects of aging on the weakening of ultrastructure and nanomechanics of aggrecan from human cartilage. Nanoscale dynamic oscillatory loading was used to quantify the evolution of tissue engineered extracellular matrix at the single cell level. The presence of growth factors such as insulin like factor-1 and osteogenicprotein-1 was found to significantly accelerate the matrix formation. Thesestudies demonstrate the proof-of-concept, and they hold great potential forquantifying the success of diagnostic and regenerative approaches at high levels of resolution (single cell and molecular levels) and for optimizing the protocols for therapeutic treatments.
Biosketch:
Lin Han obtained his B.E. degree from Tsinghua University in Beijing, P.R. of China, and his Ph.D. degree from the Massachusetts Institute of Technology in the area of Bio- and Polymeric Materials. After graduation, he worked as a quantitative analyst in Aristeia Capital, LLC from 2007 to 2009, responsible for developing and testing statistical models. Currently, he is a post-doctoral associate in the Department of Materials Science and Engineering and the Center for Biomedical Engineering at MIT. His research interests focus on exploring the nanoscale structure-property relationships of biomaterials, which aim to provide important insights into the application of disease diagnostics, tissue regeneration and bio-inspired material design.
Directions:
The Bossone Research Enterprise Center is located at the corner of 32nd and Market Streets.
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