Carbon nanotubes are capable of penetrating cell membranes to facilitate cytoplasmic delivery, but their application in medicine is still in its infancy. Much more basic research is needed before deterministic assertions — such as those contained in the company announcement — can be made about the way carbon nanotubes act biologically and pharmacologically. Furthermore, no preclinical therapeutic efficacy data exist yet for any disease using a carbon nanotube construct.The announcement was unclear about the exact nature of the studies carried out and the promised capabilities of both the carbon nanotubes and stem cells. For example, what was actually delivered by the carbon nanotubes? Proteins, DNA, small interfering RNA, or all three? Dramatically different delivery-system specifications are necessary for successful intracellular delivery and guaranteed biological activity for each of these, making the notion that ‘carbon nanotubes deliver all’ too simplistic.