Date/Time
Date(s) - 04/25/2023
3:00 pm - 4:00 pm
Location
Rhines Hall 125
Categories
Eric Appel, Ph.D.
Assistant Professor, MSE
Stanford University
Dr. Eric Appel received his BS in Chemistry and MS in Polymer Science from California Polytechnic in San Luis Obispo, CA. He performed his MS thesis research with Dr. Jim Hedrick and Dr. Robert Miller on synthesizing polymers for drug delivery applications at the IBM Almaden Research Center in San Jose, CA. He then obtained his Ph.D. in Chemistry with Prof. Oren A. Scherman at the University of Cambridge. His Ph.D. research focused on preparing dynamic and stimuli-responsive supramolecular polymeric materials. For his Ph.D. work, Eric received the Jon Weaver Ph.D. prize from the Royal Society of Chemistry and a Graduate Student Award from the Materials Research Society.
Upon graduating from Cambridge in 2012, he was awarded a Wellcome Trust Postdoctoral Fellowship to work with Prof. Robert Langer at MIT. Eric’s research at Stanford focuses on the development of biomimetic polymeric materials that can be used as tools to better understand fundamental biological processes and to engineer advanced healthcare solutions. His research has led to more than one hundred publications and 28 pending or granted patents.
Eric has received young faculty awards from the Hellman Scholars Fund, the American Diabetes Association, the American Cancer Society, and the PhRMA Foundation, and received the IUPAC Hanwha-TotalEnergies Young Polymer Scientist Award in 2022.
Abstract
Supramolecular (bio)materials exhibit highly useful properties that are impossible with traditional materials but crucial for a wide variety of emerging applications in industry or biomedicine. These materials typically employ enthalpy-dominated crosslinking interactions that become more dynamic at elevated temperatures, leading to significant softening.
Herein, we will discuss the development of a supramolecular hydrogel platform exploiting dynamic and multivalent interactions between biopolymers and nanoparticles that are strongly entropically driven, providing alternative temperature dependencies than typical for materials of this type.
We will discuss the implications of these crosslinking thermodynamics on the observed mechanical properties, demonstrating that tuning the thermodynamics and kinetics of these crosslinking interactions enable broad modulation of the mechanical properties of these materials, including their shear-dependent viscosities, temperature responsiveness, self-healing, and cargo encapsulation and controlled release. These materials exhibit viscous flow under shear stress (shear-thinning) and rapid recovery of mechanical properties when the applied stress is relaxed (self-healing), affording facile processing though direct injection or spraying approaches, making then well served for applications in industry and biomedicine.
Moreover, the hierarchical construction of these biphasic hydrogels enables innovative approaches to formulation and delivery as a diverse array of compounds over user-defined timeframes ranging from days to months. In one example, we demonstrate that these unique characteristics can be leveraged to generate vaccines exhibiting greatly enhanced magnitude, quality, and durability of immune responses. In another example, we demonstrate that these materials can be leveraged to generate new wildland fire retardant formulations enabling prophylactic treatments of high-risk landscapes for wildfire prevention.
Overall, this talk will illustrate our recent efforts exploiting dynamic and multivalent interactions between polymers and nanoparticles to generate hydrogel materials exhibiting properties not previously observed in biomaterials and affording unique opportunities in industry and biomedicine.