Engineering stem cells for biomedical applications. Stem cells can be obtained from various sources, engineered using viral and non-viral methods, and then reintroduced back into the patients’ body. These engineered stem cells can take on a number of forms. For instance, engineered stem cells encompass the genetic modification of stem cells as well as the use of stem cells for gene delivery, nanoparticle delivery and loading, and even small molecule drug delivery. Reproduced with permission.[347] Copyright 2012, Nature.