(432d) Biomedical Applications of Emulsion Templating

Emulsion templating is a recent fabrication method used to generate porous materials with exceptional control of pore architecture afforded by modulating emulsion variables. Our laboratory has developed a number of applications of polymerized high internal phase emulsions (polyHIPEs) in tissue engineering including injectable bone grafts, emulsion inks, and porous microspheres. First, fumarate-based polyHIPEs were developed that demonstrated a unique combination of properties for use as injectable, high porosity bone grafts. These materials can be stored up to one year without detriment to properties and then injected with rapid cure. Although polyHIPE tissue engineering scaffolds were first proposed in 2000, this is the first time a biodegradable polyHIPE was fabricated that cures at body temperature to a high porosity foam with compressive properties in the range of trabecular bone. Modulation of polymer chemistry has been used to generate a range of mechanical properties from rigid bone scaffolds to elastomeric, soft tissue grafts. Recently, we have taken advantage of the shear-thinning aspects of the HIPEs prior to cure to generate emulsion inks for 3D printing. These emulsion inks can be used to generate complex grafts with hierarchical porosity. Combination with thermoplastic filament printing permitted the fabrication biomimetic bone grafts with improved compressive properties without sacrificing permeability. Finally, a dual fluidics setup was used to fabricate porous microspheres for controlled release of bioactive factors. This solvent-free method provides advantages over current microsphere fabrication strategies including in-line loading of growth factors to improve loading efficiency. Overall, emulsion templating has demonstrated great potential to facilitate repair in a wide range of clinical specialties.