The scale challenge when generating kidney from human pluripotent stem cells. a. Group of segmenting nephrons within a human iPSC-derived kidney organoid showing collecting duct (GATA3, pink), distal tubule (CDH1, green), proximal tubule (LTL, blue) and glomeruli (NPHS1, red) b. Whole organoid containing approximately 100 nephrons. Inset shows relative size of panel a. c. Diagram of a developing human kidney showing relative size of organoid. d. Diagram of adult kidney. Scale bars are 70µm (a), 1mm (b), 3mm (c), 1.4cm (d). Panels a and b adapted from Takasato et al, 2015.