S5E10

Abstract

Hydrogels have desirable physical characteristics and constituents that are similar to those of many human soft tissues. They are used in many branches of regenerative medicine, including but not limited to drug delivery, tissue repair, disease modeling, and bioelectronics. However, there exist long-standing challenges that prevent the translation of hydrogels into practical use. Challenges include the fabrication of hydrogels with micrometer-sized structural features, the satisfaction of concurrent mechanical and physical design requirements, and their integration with biological tissues and engineering materials. In this talk, I will introduce novel microstructured tough hydrogels that overcome the abovementioned challenges. To facilitate fabrication and delivery while maintaining cytocompatibility, materials capable of phase separation at physiological conditions are employed to yield microstructures. The mechanics and structures of the resulting hydrogels are decoupled, circumventing common tradeoffs between these two properties. The hydrogels are amenable to cell recruitment, proliferation, and migration, and exhibit stability and fatigue resistance when exposed to extreme biomechanical stimulations present in the human body. To further enable integration with biological tissues, microstructured tough hydrogels with a liquid-solid hybrid design are developed to provide rapid adhesion. They can adhere to blood-covered wounds without applying pressure while promoting coagulation, therefore, are suitable for sealing non-compressible hemorrhages. They are easy to use and store, and demonstrate significantly improved hemostatic efficacy and biocompatibility in rats and pigs compared to available commercial products. This presentation will describe new microstructured hydrogel technologies that offer advantages for fabrication, delivery, and integration. Technological applications include tissue engineering, tissue repair, biosignal sensing, and hemorrhage management.

Introduction of speaker

Guangyu Bao obtained his Ph.D. in the Department of Mechanical Engineering at McGill University (Canada) under the supervision of Professors Luc Mongeau and Jianyu Li. His research spans diverse topics, including biomaterials, mechanics, bioelectronics, and hemostatic technologies. He received his M.S. degree in mechanical engineering from Washington University in St. Louis (USA) and B.Eng. degree in mechanical engineering and automation from Beijing University of Posts and Telecommunications (China). He is now a research scientist at SanaHeal Inc., working on developing and translating bioadhesives technologies to solve various clinical challenges.

Abstract

Drawing a direct analogy with the well-studied vibration or elastic modes, we introduce an object's fracture modes, which constitute its preferred or most natural ways of breaking. We formulate a sparsified eigenvalue problem, which we solve iteratively to obtain the n lowest-energy modes. These can be precomputed for a given shape to obtain a prefracture pattern that can substitute the state of the art for realtime applications at no runtime cost but significantly greater realism. Furthermore, any realtime impact can be projected onto our modes to obtain impact-dependent fracture patterns without the need for any online crack propagation simulation. We not only introduce this theoretically novel concept, but also show its fundamental and practical superiority in a diverse set of examples and contexts.

Introduction of speaker

Silvia Sellán is a third-year Computer Science PhD student at the University of Toronto, advised by Alec Jacobson and working in Computer Graphics and Geometry Processing. She is a Vanier Doctoral Scholar, an Adobe Research Fellow and the winner of the 2021 University of Toronto FAS Dean's Doctoral Excellence Scholarship. She has interned twice at Adobe Research under the mentorship of Noam Aigerman and twice at the Fields Institute of Mathematics. She is also an organizer of the Toronto Geometry Colloquium and a member of WiGRAPH. Before all that, she completed a B.Sc. in Mathematics and a B.Sc. in Physics at the University of Oviedo.