Dr Choo is Executive Chairman of Plasticell Ltd and Chief Executive of Progenitor Labs Ltd. He is the founder of Plasticell and served as Chief Executive and Chief Scientist of the company. Prior to his interest in stem cells he was a founder and Chief Scientist of Gendaq (acquired by Sangamo Biosciences), a biotech company that developed the zinc finger technology now used for gene editing. Previously he was a staff scientist at the MRC Laboratory of Molecular Biology, Cambridge, where he pioneered the engineering of protein-DNA interactions using combinatorial methods under Nobel laureate Sir Aaron Klug.