Dr. Eric Appel, Associate Professor of Materials Science and Engineering, Stanford University

Supramolecular biomaterials 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 for co-delivery of immunostimulatory cytokines and CAR-T cells to improve cancer treatments. 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.

Hosted by: Dr. Alexandra Rutz