Traction Force in Physics and Biology: Collective cell and tissue mechanics, durotaxis, and the physics of cleansing and moisturizing.

Dr. Guy K. German,Department of Bioengineering, SUNY Binghamton

Hopeman 224

Forces at interfaces are ubiquitous in nature and the need to measure such forces arises in many scientific disciplines. Peeling paint, crawling cells and drying skin all create interfacial traction forces. Traction Force Microscopy (TFM) is a powerful technique employed to calculate interfacial forces from measured displacements in a deformable substrate. Originally developed for adherent cells crawling on a surface, the method has no inherent size or force scale. By adjusting the elastic modulus of the substrate, the size of tracer particles used to measure displacements and the imaged field of view, a wide range of length scales and forces are accessible. In order to elucidate the broad range of applications that can be explored using TFM, I will discuss research performed on the emergence of apparent surface tensions in epithelial cellular colonies, heterogeneous drying behavior in the outermost layer of skin (stratum corneum), the effect of cosmetic soaps and moisturizers on the mechanical properties and drying stresses in healthy and disordered skin and durotaxis in water drops; the ability, demonstrated by many eukaryotic cell types, to move along gradients in substrate stiffness.