Dr Noburo Sato's lab has found that the use of blebbistatin, a non-muscle myosin II (NMII) inhibitor, enhances cloning efficiency of human ES and iPS cells. The effect of blebbistatin is comparable to that of ROCK inhibitor, Y-27632 in both adherent monolayer and suspension culture conditions. shRNA-mediated knockdown of NMII heavy chain (NMHCIIA) also prevented cell death in human pluripotent stem cells. Additionally, the use of blebbistatin supported long-term cultures of human ES and iPS cells on poly-D-lysine (PDL) substrate, which helps bring us closer to creating fully-defined culture conditions for human pluripotent stem cells. Dr. Sato's work was published in Nature Communications:
http://www.nature.com/ncomms/journal/v1/n6/abs/ncomms1074.html