Fig 1. Fabrication of cell-loss-free (CLF) concave microwell array for multi-cellular tumoroids (MCTs) formation.

(a) The PDMS CLF concave microwell array was fabricated into a size suitable for the cell culture plate (i). The meniscus concave shape bottom within the microwells was confirmed by SEM image (ii). It was confirmed that the PDMS concave microwell array consisting of a microwell with a wall 1 mm high for separating each well (iii). (b) Cell sliding along spiky walls by gravity after initial cell trapping in CLF microwell array. (c) Compact spheroids by the cell mixture with cancer and fibroblasts, and obtainment of a large number of MCTs in the fabricated CLF concave microwell array.