Cancer immunotherapies based on the ability of T cells to recognize and kill tumor cells (TCs), including immune checkpoint blockades (ICBs) and chimeric antigen receptor (CAR) T cell therapy, have...

Structure changes mediated by anisotropic volume changes of stimuli‐responsive hydrogels are useful for many research fields, yet relatively simple structured objects are mostly used due to limitation in fabrication methods. To fabricate complex 3 dimensional (3D) structures that undergo structure changes in response to external stimuli, jammed microgel‐based inks containing precursors of stimuli‐responsive hydrogels are developed for extrusion‐based 3D printing. Specifically, the jammed microgel‐based inks are prepared by absorbing precursors of poly(acrylic acid) or poly(N‐isopropylacrylamide) in poly(acrylamide) (PAAm) microgels, and jamming them. The inks exhibit shear‐thinning and self‐healing properties that allow extrusion of the inks through a nozzle and rapid stabilization after printing. Stimuli‐mediated volume changes are observed for the extruded structures when they are post‐crosslinked by UV light to form interpenetrating networks of PAAm microgels and stimuli‐responsive hydrogels. Using this method, a dumbbell‐shaped object that can transform to a biconvex shape, and a gripper that can grasp and lift an object in response to stimuli are 3D‐printed. The jammed microgel‐based 3D printing strategy is a versatile method useful for variety of applications as diverse types of monomers absorbable in the microgels can be used to fabricate complex 3D objects transformable by external stimuli.

No abstract

Cells in 3D behave differently than cells in 2D. We develop a new method for the fabrication of 2D and 3D cell cluster arrays on an identical substrate using a cell-friendly photoresist, which enables comparative study between cells in 2D and 3D cell clusters. The fabricated cell cluster arrays maintain their structure up to 3 days with good viability. Using this method, 2D and 3D cancer cell clusters with comparable sizes are fabricated, and natural killer (NK) cell cytotoxicity assays are performed to assess how dimensionality of cancer cell clusters influence their susceptibility to immune cell-mediated killing.