“…Human iPSCs were cultured on Matrigel‐coated plates (BD Biosciences, San Diego, CA, http://www.bdbiosciences.com) in iPSC growth medium containing Dulbecco's modified Eagle's medium (DMEM)/F12 (Mediatech, Manassas, VA, http://www.cellgro.com), 20% vol/vol knockout serum replacement (SR; Life Technologies, Rockville, MD, http://www.lifetech.com), 1% vol/vol nonessential amino acids (Mediatech), 2 mM l ‐glutamine (Mediatech), 100 mM β‐mercaptoethanol (Life Technologies), and 10 ng/ml basic fibroblast factor (bFGF; Life Technologies). To enable single‐cell feeder‐free culture of iPSCs, growth media was supplemented with small molecule 4 (SMC4) cocktail, as previously described [11, 12]. SMC4 media additive contains 0.4 µM PD0325901 (Biovision, Milpitas, CA, http://www.biovision.com), 1 µM CHIR99021 (Biovision), 5 µM Thiazovivin (synthesized at Fate Therapeutics), and 2 µM SB431542 (Biovision).…”