One-Step Formation of Microporous Hydrogel Sponges Encapsulating Living Cells by Utilizing Bicontinuous Dispersion of Aqueous Polymer Solutions

With the recent progress in three-dimensional (3D) cell culture techniques for regenerative medicine and drug development, hydrogel-based tissue engineering approaches that can precisely organize cells into functional formats have attracted increasing attention. However, challenges remain in creating continuous microconduits within hydrogels to effectively deliver oxygen and nutrients to the embedded cells. Here we propose a one-step, fully liquid state, and all-aqueous process to create porous hydrogels that can encapsulate living cells without the need for extensive processing protocols, including the incorporation and removal of sacrificial materials. An unusual bicontinuous state of aqueous two-phase dispersion was utilized, and one of the two phases, encapsulating living cells, was rapidly photo-cross-linked to form hydrogel sponges. We optimized the volumetric mixing ratio of gelatin methacrylate (GelMA)-rich and polyethylene glycol (PEG)-rich solutions and investigated the effects of the formed con...