4. Cellular interactions and regulatory requirements

At the cellular level, nanoparticles can present different types of toxicity: inflammatory response, genotoxicity, immunotoxicity and reproductive toxicity. Nanoparticles can also enhance the toxicity of active substances, through targeting. Finally, they can increase the toxicity of additives, leading to unexpected toxicities, although toxicological studies carried out on nanomedicines often tend to overlook these additives. Understanding internalization mechanisms is certainly one of the key steps in addressing toxicity issues.