The importance of assessing immunosafety of engineered nanomaterials
Assessment of nanosafety, with particular regard to nanomedicines and health-related nanomaterials, should consider the possible effects on the immune system with great care. The immune system is responsible for defending the integrity of our body and maintaining its health. Possible alterations of the normal functions of the immune system, as a consequence of interaction with nanoparticles, must be avoided as they can cause severe pathological derangements. It is expected that nanotechnologies applied in medicine (nanodrugs, nano-imaging tools, nano-delivery systems, nanodevices) will greatly improve the quality of the diagnostic and therapeutic intervention in the near future, e.g., allowing us to target with great precision secluded organs or tissues (brain, metastatic tumours, etc.). In order to speed up the development of such nanotools, the safety of the nanomaterials should be evaluated at every phase of development (from synthesis of the raw materials to the final formulation). To this end, it will be necessary to design and implement robust and representative methods able to predict the immune-related risk of developing diseases. Besides the exquisitely immunological problem of selecting representative endpoints predictive of the risk of developing disease, assay results turned out to be significantly biased by artefactual interference of the nanomaterials or contaminating agents with the assay protocol. Therefore, available standardised immunological assays are not suited in most cases for detecting nanoparticle effects, and should therefore be custom-adapted or re-designed to this end. A major issue in immunosafety assay design is the need for standardisation and ease of applicability of the validated assays. In this context, in vitro assays are greatly preferred because of their high reproducibility, in addition to avoiding the use of large numbers of experimental animals. To increase relevance, the possibility of employing in vitro models of human primary cells, rather than animal tissues or transformed/tumour cell lines, is of great importance.