Pre-Programmed Rod-Shaped Microgels to Create Multi-Directional Anisogels for 3D Tissue Engineering

摘要

Micron-scale anisometric microgels have received increasing attentionto replace macromolecule solutions to create injectable 3D regenerativehydrogels. Interlinking these rod-shaped microgels results in microporousconstructs, while incorporating magnetic nanoparticles inside the microgelsenables their alignment to introduce directionality. This report demonstratesthat the angle of microgel alignment in a static external magnetic field canbe pre-programmed, broadening their applicability to artificially assembleinto specific architectures. The magnetic rod-shaped polyethylene glycolmicrogels are prepared via in mold polymerization. Ellipsoidal maghemitenanoparticles, integrated as responsive fillers are pre-aligned either parallelor orthogonal to the long axis of the microgel with a weak magnetic fieldduring rod fabrication to implement additional control over their magneticorientation and allow their precise manipulation and actuation. The magneticresponse of the microgels to static and rotating magnetic fields is discusseddepending on various process and design parameters, such as magnetic fieldstrength, angular frequency, and pre-alignment. Finally, the applicability of theapproach for tissue engineering is highlighted by growing mouse fibroblastsin three dimensions within Anisogels, i. e., hydrogels containing a mixtureof rods with both a parallel and orthogonal orientation, marking a new steptoward more advanced functional cell templating for tissue engineering.