MechE Colloquium: Mechanobiology of soft human tissue: a mechanics perspective

Abstract: Mechanotherapy is a new field based on emerging evidence of the influence of mechanical processes on physiology and pathology of our organism. Well known examples are the relation between hypertension and progressive vascular stiffening, or the link between tissue stretch and the formation of hypertrophic scars, or the detrimental loop leading to increasing tissue rigidity in several fibrotic diseases. Mechanobiology is a research field at the interface between biology and mechanics which investigates the relationship between mechanical factors and cell behavior.
Mechanobiology as pursued by biologists mainly analyzes cell internal mechanisms and processes (pathways) activated by mechanical stimuli. The latter typically include tissue deformation, alteration of the stiffness of the extracellular matrix, and/or flow induced shear stresses. As mechanicians, we take a different approach and analyze the multiscale mechanical behavior of soft tissues in order to characterize the biophysical environment of cells. Thereby we identified a few factors influencing cell behavior which were neglected so far. This knowledge improves our understanding of mechanotransduction and could potentially contribute to the identification of new targets for mechanotherapy. 
Two applications will be presented: (i) alteration of the electro-chemo-mechanical environment of dermal cells associated with skin stretching, analyzed using a quadriphasic model of human dermis; (ii) mechanical damage of endothelial monolayers associated with monotonic and cyclic stretching, rationalized through a discrete network model of endothelial cells. 

Biography: Edoardo Mazza has been Full Professor of Mechanics at the Institute of Mechanical Systems in the Department of Mechanical and Process Engineering since 2010. He studied mechanical engineering at ETH Zurich and received his doctorate at ETH in 1997. For his dissertation on the Mechanical Behavior of Micrometer Sized Structures he was awarded the ETH medal. He has been working in industry from 1997 to 2001. At Alstom Power he was group leader in the steam turbine R&D department and was responsible for the mechanical analysis of stationary and rotatory components. In 2002 he was appointed as Assistant Professor, in 2006 as Associate Professor of Mechanics at ETH Zurich. Since 2006 he also leads the laboratory "Experimental Continuum Mechanics" of Empa, the Federal Laboratories for Materials Science and Technology. From 2016 until 2020 he has been president of ETH lecturers’ conference (KdL). From 2021 until 2023 he has been Head of Department of D-​MAVT, the Mechanical and Process Engineering Department of ETH Zurich.
His research deals with experimental continuum mechanics, applied for the solution of challenging engineering problems. Novel experimental techniques are developed for the characterization of the mechanical response of structures and materials. The deformation behavior of soft biological tissues in human organs is analyzed at each relevant length scale, and described with appropriate mathematical models. Applications in mechanobiology address the chemo-​physical factors of the extracellular environment influencing cell behavior. Tissue engineered and synthetic materials, mesh implants and stents are evaluated in terms of “mechanical biocompatibility”.