Steven Caliari, Associate Professor, University of Virginia

"Phototunable control of hydrogel stress relaxation for creating 3D cellular microenvironments"

Abstract:

Tissues exhibit spatially heterogeneous viscoelastic mechanics characterized by stress relaxation timescales spanning seconds to hours. Viscoelasticity plays a pivotal role in diverse biological processes including fibroblast activation, cancer progression, and stem cell differentiation. Despite its significance, dissecting how viscoelasticity regulates in vivo phenomena remains challenging due to the complex interplay of diverse cell types, extracellular matrix components, and signaling molecules. Toward the creation of in vitro models deconstructing this complexity, we invented the first hydrogel 3D cell culture platform with photopatterned spatiotemporal control of viscoelasticity and stress relaxation. This seminar will discuss our latest results on designing cell-instructive hyaluronic acid hydrogels combining dynamic covalent and supramolecular interactions using thiol-ene photochemistry. Although light-mediated thiol-ene addition is considered a highly-specific ‘click’ reaction, I will also highlight our unexpected discovery that norbornene homopolymerization (norbornenes reacting with other norbornenes instead of thiols) can significantly impact hydrogel network formation.

Bio:

Steven joined the faculty of the University of Virginia in 2016 as an Assistant Professor in the Department of Chemical Engineering with a secondary appointment in the Department of Biomedical Engineering. He was promoted to Associate Professor in 2022. Prior to joining UVA he was an NIH Postdoctoral Fellow in the Department of Bioengineering at the University of Pennsylvania. Steven completed his B.S. in Chemical Engineering at the University of Florida and received both his M.S. and Ph.D. in Chemical Engineering from the University of Illinois at Urbana-Champaign. His lab designs biomaterials to study the dynamic reciprocity between cells and their microenvironment, applying these platforms to address fundamental human health challenges in understanding disease and engineering tissues. Steven has received the NIH (NIGMS) Maximizing Investigators’ Research Award (MIRA), NSF CAREER award, and was named a 2021 Young Innovator in Cellular and Molecular Bioengineering. His lab is grateful for generous support over the years from the NIH, DoD, NSF, V Foundation, Virginia Innovation Partnership Corporation, and UVA-Coulter Translational Research Partnership.