Yoshiki Sasai (?? ??, Sasai Yoshiki, 5 March 1962 – 5 August 2014) was a stem cell biologist.
He developed methods to guide human embryonic stem cells (hESCs) into forming brain cortex, eyes, and other organs in tissue culture.
Sasai was one of the founding leaders of the RIKEN Center for Developmental Biology (CDB) in Kobe, a premier research institute for biology in Japan and Director of the Laboratory for Organogenesis and Neurogenesis at the research institute RIKEN.
Sasai was best known for developing new methods to grow stem cells into organ-like structures.In 2012, Sasai became the first stem cell researcher to grow an optic cup from human cells.On August 5, 2014, he was found dead hanging at the RIKEN institute.