Nanosafety: towards safer design of nanomedicines

In 2010, the Journal of Internal Medicine published a collection of review articles on the application of nanotechnologies in regenerative medicine and drug delivery ([1] and references therein). The series also included reviews on nanotoxicology. Toxicology or safety assessment is certainly an integral part of any new medical technology, and the nanotechnologies are no exception. The fact that nanomaterials are similar in size to intraand extracellular biological systems yet can be engineered to have various functions makes these materials attractive for medical applications [2]. However, the same, novel properties that arise at the nanoscale may also lead to unexpected toxicities of nanomaterials, that is, toxicities not anticipated from materials of the same composition in bulk form. Thus, nanotoxicology is emerging as a scientific discipline with the aim of studying the undesirable interference between man-made or engineered nanomaterials and the nanoscale machineries of biological systems [3]. It is important to ask whether there are any unique toxicities or phenomena associated with nanomaterials; the answer is yes. Indeed, as recently pointed out [3], one of the key features of nanomaterials, and one that may suggest novel and unanticipated health risks, is the propensity of such materials to cross biological barriers. In other words, the geography of the biological response (due to translocation of nanoparticles to organs and tissues distal to their portal of entry into the human body) may be as important as the anatomy of the nanoparticle itself (i.e. the chemical composition of the nanoparticle, along with its size and shape, and so on).