Events Calendar

Aerospace and Mechanical Engineering Seminar Series

Speaker: Guruswami Ravichandran, John E. Goode, Jr. Professor of Aerospace and Professor of Mechanical Engineering and Director, Graduate Aerospace Laboratories at the California Institute of Technology, Pasadena, CA

Talk Title: Mechanics of Cell-Matrix Interactions in Three-Dimensions

Series: Aerospace and Mechanical Engineering Seminar Series

Abstract: Biological cells are complex living systems that can be viewed as micromachines, which derive their many mechanical functions from the molecular motors within the cell. The forces cells apply to their surroundings control processes such as growth, adhesion, development, and migration. Experimental techniques have primarily focused on measuring tractions applied by cells to synthetic two-dimensional substrates, which do not mimic in vivo conditions for most cell types. This talk will describe an experimental approach to quantify cell tractions in a natural three-dimensional matrix. Cells and their surrounding matrix are imaged in three dimensions with confocal microscopy; cell-induced matrix displacements are computed using digital volume correlation; and tractions are computed directly from the full-field displacement data. The technique is used to investigate how cells employ physical forces during cell division, spreading and sensing. In a three-dimensional matrix, dividing cells apply tensile force to the matrix through thin, persistent extensions that in turn direct the orientation and location of the daughter cells. During spreading, cells extend thin protrusions into the matrix and apply force using these protrusions. The cell forces induce deformations along directed linear paths in the fibrous matrix. A constitutive model is developed that accurately predicts the propagation of cell-induced displacements through the matrix. The model describes how cells use nonlinearities in the fibrous matrix to enable long-range cell-cell mechanical communication.

Biography: Guruswami Ravichandran is the John E. Goode, Jr. Professor of Aerospace and Professor of Mechanical Engineering and Director of the Graduate Aerospace Laboratories (GALCIT) at the California Institute of Technology. He received his B.E. (Honors) in Mechanical Engineering from the University of Madras in 1981, Sc.M. in Engineering and Applied Mathematics in 1983 and 1984, respectively, and Ph.D. in Solid Mechanics and Structures from Brown University in 1986. He is a Fellow of the Society for Experimental Mechanics (SEM) and the American Society of Mechanical Engineers (ASME). His awards include Lazan and Hetenyi awards from SEM and Charles Russ Richards Memorial Award from Pi Tau Sigma and ASME. He was awarded Doctor honoris causa by Paul Verlaine University, France in 2006 and Chevalier de l'ordre des Palmes Academiques by the Republic of France in 2011. His research interest is in the area of mechanics of materials, with emphasis on deformation, damage and failure, active materials, biomaterials and cell mechanics, and experimental methods.

Host: Paul Ronney

Location: Seaver Science Library (SSL) - 150

Audiences: Everyone Is Invited

Contact: Valerie Childress