Abstract: Photocrosslinkable precursors (small molecules or polymers) undergo rapid crosslinking upon photoirradiation, forming covalently crosslinked hydrogels. The spatiotemporally controlled crosslinking, which can be achieved in situ, encourages the utility of photocrosslinked hydrogels in biomedicine as bioadhesives, bioprinting inks, and extracellular matrix mimics. However, the low viscosity of the precursor solutions results in handling difficulties owing to unwanted flows and dilution and compromises the strength of the photocrosslinked hydrogels. In this talk, I will introduce oppositely charged triblock polyelectrolytes as additives for precursor solutions that transform the precursor solution into a self-assembled polyelectrolyte complex (PEC) hydrogel with enhanced shear strength and viscosity, providing interim protection against precursor dilution and mitigating secondary flows. The PEC network also augments the properties of the photocrosslinked hydrogels. Crosslinking of the precursors upon photoirradiation results in the formation of interpenetrating polymer network hydrogels with PEC and covalently-linked networks that exhibit shear moduli exceeding the linear combination of the moduli of the constituent networks and overcome the tensile strength–extensibility tradeoff that restricts the performance of covalently-linked hydrogels. The reinforcement approach will be shown to be broadly compatible with photocrosslinkable precursors, not require any modification of the precursors, and introduce minimal processing steps, paving the way for broader translation of photocrosslinkable materials for biomedical applications.
Bio: Samanvaya is an Assistant Professor of Chemical and Biomolecular Engineering at UCLA. He completed his undergraduate and master’s degrees from IIT Kanpur and his Ph.D. from Cornell University, all in Chemical Engineering. At IIT Kanpur, he worked with Prof. Ashutosh Sharma on instabilities in thin films. At Cornell, he worked with Prof. Lynden Archer on the structure and properties of polymer nanocomposites and nanoparticle dispersions. After his Ph.D., Samanvaya pursued postdoctoral research on polyelectrolyte solutions and complexes with Prof. Matthew Tirrell at The University of Chicago. Samanvaya's current research interests are in investigating the influence of diverse intermolecular interactions on material structure and properties, with a broader aim to combine this fundamental understanding with molecular engineering and self-assembly processes to improve materials design. He has published over 40 research articles and has received several awards, including Austin Hooey Graduate Research Excellence Recognition Award at Cornell University, RSC Researcher Mobility Grant, AIChE 35 under 35 award, the NSF CAREER Award, and the ACS PMSE Young Investigator Award.
Lab website: https://www.srivastava-lab.net/