Representative images of MDA-MB-231 aggregates or fibroblast spheroids on day 0 (before [CAR-]T cell treatment), and on days 1 and 8 after tumor-on-chip perfusion with control T cells or CAR-T cells. MDA-MB-231 tumor cells express GFP and are pseudocolored cyan. Fibroblasts—representing nonmalignant tissue as a control—were labeled with CellTracker 5-chloromethylfluorescein diacetate (CMFDA) and pseudocolored cyan. Control T cells and CAR-T cells were labeled with CellTracker deep red. The yellow dashed line marks the region of interest of each tumor aggregate or fibroblast spheroid. MvECs were present in all chips. Scale bars, 200 μm.
