Everything in the human body, with the exception of teeth and bone, is soft, squishy, and nearly free-form in structural organization and geometric construction - virtually the antithesis of traditional engineering materials. However, soft biological systems, including cells, tissues, and organs, often bear significant stresses under large strains, perform complex heat and mass transport functions, and continuously remodel and rebuild in response to engineering-like challenges. Soft Matter Engineering is an emerging field that focuses on challenges in the design, use, and manufacturing of structures, assemblies, and devices that are “soft” or interface with “soft matter”. This talk will discuss the development of ultra-low contact pressure instrumentation for probing delicate interfaces during contact and sliding. The instruments were built onto microscope frames to enable in situ optical microscopy and confocal imaging. A wide range of experiments were performed to explore models of lubricity in hydrogel surfaces based on theories of viscous dissipation within a surface region estimated to be on the order of a single polymer mesh size. The applied focus of this research is towards biocompatibility and comfort in contact lenses. Experiments with corneal epithelial cells in contact with hydrogel probes revealed a strong pro-inflammatory response triggered by shear stresses as low as ~100 Pa. These findings may be broadly applicable to epithelial signalling in response to direct contact stimulation and shear and have implications in biocompatibility and tumor inflammatory signalling. The talk will briefly touch on the use of soft granular microgels as a potential route for the precision fabrication and engineering of 3D tumoroids and microtissues as models for interfacial engineering studies in cancer and human biology.
Dr. Angela A. Pitenis is a researcher in the Soft Matter Engineering Center in the Department of Mechanical and Aerospace Engineering at the University of Florida. Her research is in interfacial engineering, with a particular focus on soft, dynamic surfaces. Current activities are focused on the tissue and tumor microenvironment, and this research uses contact mechanics, soft condensed matter physics, surface science, and biomedicine. Angela’s work has ranged from exploring the mechanochemistry of fluoropolymer interfaces during sliding, to hydrogel lubricity, to recently uncovering the mechanisms of friction-induced inflammation by gently rubbing hydrogels against corneal epithelial cells in vitro.