Budapest Meeting Scientific Questions
During the last meeting in Budapest of NanoToes as we were starting the work with the new fellows interesting questions raised. Which are the tools a nanosafety expert needs to practice their expertise? An interesting thing is that in our lab, where we prepare a wide range of inorganic nanoparticles, we never observed cross-contamination, there is no silver or cadmium with gold, nor titanium with cobalt oxide, nor iron with cerium oxide, or any other combination. However, the material that has been in contact with nanoparticles normally shows traces of it. Thus, it seems that nanoparticles are persistent but not propagating, what is important in order to establish its safety. Other issue was if we should standarize, or at least unify, biological tests in the different laboratories, and the answer was no. What is bold but makes sense. The different strategies to evaluate the biological impact and toxicity on cells or living beings are not good or bad, they can be more or less useful in order to answer detailed questions. But once the behavior of nanostructures is fully understood then, all the biological questions are decent if properly formulated. And if the question is properly asked, the answer should be easy and straight forward. Finally, something that also was a matter of concern, when extrapolating from the in vitro models to in vivo predictions, was the oxygen preassure/concentration inside the body, something that it is not so simple. The issues steams from the fact that Reactive Oxygen Species (ROS) production is becoming a universal paradigm of the toxicity of inorganic nanoparticles, but when this is tested in in vitro cell cultures, air is not so far from the cells and the oxygen concentration in the cell culture media is not so low. But what happens if oxygen preassure/concentration is lower inside the body, will inorganic oxide nanoparticles still induce the production of ROS or will it decreases as do the available oxygen concentration decrease? Is this paradigm useful for all cells –ROS induction- or only for epithelial cells exposed to the exterior?