The normal paradigm for developing a new nanomedical system is to start with an in vitro cell line (usually human) system and then progress to excised, or biopsied , tissue from a human (ex vivo). Finally, to better simulate the effects of a total organism, we begin in vivo studies, usually on an animal system. This has been the general paradigm for decades. Now we have new “organ-on-a-chip” in vitro models that generate organ-like human tissue on an in vitro format. There have even been more recent promising efforts at generating “human-on-a-chip” technologies.