Events Calendar

Systems Cellular-Molecular Bioengineering Distinguished Speaker Series

Speaker: Elliot Botvinick, Associate Professor of Biomedical Engineering, UC Irvine

Talk Title: Feeling Pericellular Mechanical Heterogeneities

Abstract: While there is strong evidence for roles of bulk stromal stiffness in cell regulation, roles for the pericellular mechanical microenvironment are less clear, in large part due to the difficulty of measurement. My group implements automated Active Microrheology (aAMR), an optical tweezers technology, to probe extracellular stiffness and map it in the volume surrounding cells. Our aAMR applies sinusoidal optical forces onto microbeads embedded within natural extracellular matrices (ECMs), including those comprised of fibrin and type 1 collagen. As in the case of passive microrheology, aAMR reports the complex material response function of the ECM just surrounding each microbead. Different from passive methods, aAMR is valid for systems not in thermal equilibrium, as is typical for regions of the ECM near to contractile cells. Our aAMR microscope can probe many beads surrounding each cell to map the mechanical landscape, allowing us to seek correlations between local stiffness distributions and cell properties such as contractility, signaling, and differentiation. I will present specific examples for which the distribution of pericellular stiffness correlates with cell phenotype/state including: MT1-MMP deficient mesenchymal stem cells, human aortic smooth muscle cells with compromised contractility and fibrosarcoma cells cultured in type 1 collagen gels.

Biography: My research program has two areas of focus: mechanobiology and medical device development. My research group uses photonic tools to investigate roles for mechanical forces and physical properties in the regulation of tissues. We have expertise in the areas of photonics, laser ablation, imaging, tissue engineering and mechanobiology. Specifically, we develop instrumentation and devices for quantitative biophysical measurements towards the study of single molecule biophysics and cell-tissue physical interactions. In particular, we use optical tweezers to measure single receptor-ligand interactions and have discovered strong evidence for the role of ligand-endocytic forces in the activation of the Notch receptor. We also use optical tweezers/scissors to measure local continuum viscoelastic parameters in order to seek correlations between microenvironment mechanics and cell function. We have applied these tools to test mechanical hypotheses in the areas of cancer biology, microvascular morphogenesis, tissue engineering, stem cell biology and the transition of ductal carcinoma in situ into an invasive phenotype.

Host: Megan McCain

More Information: botvinick_flyer.pdf

Location: Corwin D. Denney Research Center (DRB) - 146

Audiences: Everyone Is Invited

Contact: Megan McCain