Abstract
Due to the large diversity of nanomaterials and to their partly unknown behavior in human, nanomedicine regulation is taking shape at a slow pace. Here, I discuss the following aspects linked with the emergence of such regulation: (i) nanomaterial definition/classification, which may be extended beyond the sole notion of size or dimension and overcome the confusion arising from the distinction between their intentional and non-intentional use or exposure, (ii) nanomaterial interacting behaviors that lead to the formation of aggregates or agglomerates depending on their interacting strength, opsonization following capture of biological material at their surface, and the apparition of assemblies of dispersed or soluble nanomaterials depending on their level of degradation in a given medium, (iii) nanomaterial dose whose value depends on the method used for measurement and on the type of dose considered (injected versus effective), (iv) the different steps of nanomaterial preparation whose most critical one is often sterilization that should remove bacterial contamination without affecting nanomaterial properties, (v) the different characterization methods and properties that they measure, (vi) the toxicological assessment of these materials that necessitates accurately selecting the toxicity tests and associated operating conditions, (vii) nanomaterial biodistribution properties that notably depend on the frequency with which the organism is monitored, the types of studied tissues/organs, and the nature of the nanomaterial used for the study (transformed or not), (viii) the risk analysis that should determine the severity of potential damages caused by a nanomaterial as a function of the probability of this damage.
