**8. Conclusion**

Accurate risk assessment is an interdisciplinary approach, where acquiring information and processing is a never-ending ordeal. Therefore, an ethical yet smart approach is needed for studying risks associated with nanoparticles. Only the understanding of the mechanisms of toxicity can enable future endeavors towards strategies of safe nanomaterial design and stress recovery solutions.

*In vivo* investigations are largely failing to correlate with clinical trials for various reasons. Many pharmaceutical companies have been using rat, monkey and dog models to evaluate toxicity. These are time consuming and cost intensive with very little productivity in terms of actual drugs reaching the market. *In vitro* investigations have the advantage of being cost and time effective and reduces unethical animal sacrifices and cruelty. Any meaningful result can further be screened out for animal testing, if necessary.

Another advantage of *in vitro* models is that it can be developed into 3D cultures and organ on chip innovations to more accurately predict clinical outcomes [32]. Some recent publications show that the level of prediction is even higher than that of *in vivo* investigations, since there is the scope to study and test human tissue functions along with the mechanical fluidic motions that accurately mimic conditions in the human body.

Thus, it is highly intuitive to encourage young researchers to look at a problem holistically and design best possible routes towards solutions that may lead to implementation and relief. An appreciation of resources and time is vital to avoid wasting them in illogical endeavors. An open mind is to be inculcated that although is enriched with knowledge but chooses to not be limited by it.
