Chan et al (1) demonstrated that reprogramming efficiency under feeder-free conditions was lower, but that all of the iPS cells generated were fully (not partially) reprogrammed. Therefore, it seems that culture conditions have an important role in the reprogramming process. That is why we recommend STEMCELL Technologies’ feeder-free, defined, and xeno-free media for reprogramming fibroblasts (TeSR-E7) or blood cells (ReproTeSR), which generate recognizable iPS cells with less differentiated or partially reprogrammed background cell growth.
(1) Chan EM, et al. Nat Biotechnol 27(11): 1033–7, 2009