(267b) Tissue Response and Integration in Biomaterial Implants Derived from Morphologically Unique Emulsion Gels

The long-term success of biomaterial implants is dependent largely on the ability to mediate the host tissue foreign body response and allow adequate void for new tissue and vasculature formation. Modulating the material chemistry of implants has been shown to produce varying levels of inflammatory tissue response. Additionally, micro-topological features and overall 3-D morphology have been implicated as crucial factors in long-term implant success. In this talk, we will demonstrate how a new class of morphologically unique emulsion gels can be utilized for synthesizing biomaterial implants, and how their unique morphological attributes translate to foreign body response mitigation and host tissue integration. Bicontinuous interfacially jammed emulsion gels (bijels) are formed via colloidal silica self-assembly during spinodal decomposition in partially miscible binary liquid solutions. Particles carefully tuned to mutually wet the respective fluid phases adsorb at the fluid-fluid interface at the onset of temperature-driven phase separation. Phase separation is kinetically halted once the interface is fully occupied by particles, and a bijel is formed as the mixture undergoes a gelation transition. The resulting gel is comprised of co-continuous, fully percolating fluid micro-channels with consistent curvature and uniform, tunable channel diameter that are separated by a silica monolayer. The bijel offers a robust template for synthesizing uniquely structured biomaterials from various hydrogel precursors with a number of advantages for long-term implant applications. Firstly, micro-channel domains may be tuned to prevent cells from organizing in dense, encapsulating layers at the tissue-implant interface. Secondly, the consistent curvature of the penetrating micro-channels may promote a favorable interaction between immune cells and implant surfaces. Lastly, the fully penetrating nature of the micro-channels allows for full utilization of the void phase in generating new tissue and dense vascular networks desired in long-term implantable materials.