Biophysical Society Thematic Meeting | Singapore

Mechanobiology of Disease

Poster Abstracts

63-POS Board 63 Atomic Force Microscopy as Tool to Selectively Investigate the Mehcanical Properties of Different Components of Cytoskeleton in Muscle Fibres in Vitro Roberto Raiteri 1 , Mariateresa Tedesco 1 , Ilaria Pulsoni 1 , Christopher Ward 2 . 1 University of Genova, Genova, Italy, 2 University of Maryland, School of Medicine, Baltimore, MD, USA. Atomic force microscopy (AFM) allows to measure the transversal stiffness of the sub- sarcolemma region of cells with sub-micrometer lateral and vertical resolution. By AFM nanoindentation measurements we investigated the changes in stiffness of isolated skeletal muscle fibres induced by acute doses of different substances capable to selectively induce changes in the organization of microtubules and intermediate filaments, namely colchicine, taxol, parthenolide, and Withaferin A. Our results confirm that AFM nanoindentation performed at different penetration depths allows to selectively and quantitatively probe the response of different regions of the sarcolemma localized in the first few hundreds of nanometers below the sarcolemma. Such capability represents a powerful tool, complementary to other in vitro and in vivo techniques, to investigate the mechano-transduction at the basis of generation and progression muscle pathologies such as dystrophies. Board 66 Nanoscale Optomechanical Actuators for Controlling Mechanotransduction in Living Cells Khalid Salaita 1,2 , Zheng Liu 1 , Victor Ma 1 . 1 Emory University, Atlanta, GA, USA, 2 Emory University and Georgia Institute of Technology, Atlanta, GA, USA. Optical approaches for the controlling biological systems are transforming the field of cell biology, as exemplified by caged or photoswitchable molecules and by optogenetic constructs. Similarly, methods to harness light for delivering precise physical inputs to biological systems could potentially transform the study of mechanotransduction. Toward this goal, I will describe our efforts aimed at developing optomechanical actuator nanoparticles to manipulate receptor mechanics with high spatiotemporal resolution using near-infrared illumination (Nature Methods 2016). Nanoparticles are comprised of a gold nanorod coated with a thermoresponsive polymer shell. Illumination leads to local heating, and particle collapse, thus delivering piconewton forces to specific cell surface receptors with high spatial (~micron scale) and temporal resolution (msec timescales). Optomechanical actuators were used to exert forces through the integrin receptors, thus mechanically controlling focal adhesion formation, cell protrusion, and cell migration in living cells. This new approach to controlling mechanotransduction circuits allows for optically controlling cell migration without the use of genetic engineering. 66-POS

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