(395c) Cell Delivery Systems Via Complex Emulsion Templated Hydrogels

Multiphase emulsions with co-continuous and tunable internal microstructure are formed via colloidal silica self-assembly during spinodal decomposition in partially miscible binary solutions. Silica particles tuned to mutually wet the respective fluid phases strongly absorb at the interface at the onset of temperature-driven phase separation. Demixing comes to a kinetic halt once the interfacial area is sufficiently reduced to only accommodate particles, and the mixture undergoes a remarkable gelation transition. This now kinetically arrested, bicontinuous interfacially jammed emulsion gel (bijel) is comprised of co-continuous, fully percolating channels separated by a silica monolayer. Bijels provide a tunable template for synthesizing uniquely structured soft materials containing penetrating microchannels with consistent curvature. By selecting biocompatible polymers, the inherent properties of these templated materials can be utilized for probing applications in regenerative cell delivery and tissue engineering. We have synthesized a novel cell delivery system that contains fully penetrating and uniform void channels with tunable diameter for cell loading and unloading; exhibits robust mechanical properties brought about by the repetitive structure of the percolating polymer phase; and can be filled with common cell-friendly, soft matrix environments. These particular properties are exclusively afforded by this new class of soft materials because of their unique microstructure. In this talk, we will demonstrate how these bijel-templated hydrogels are utilized as cell delivery systems, with particular emphasis on cell seeding and unloading via chemoattractant gradients. Further, we will discuss the broader applications of these bijel-derived scaffolds for tissue engineering, particularly their application as biocompatible, densely vascularized membranes for therapeutic tissue implants.