Do nanoparticles cause hormesis?

Hormesis is an effect when an agent toxic in major amounts (stressor), in minor doses causes a beneficial effect. The early reaction of the organism due to the stressor increases defence strategies, in effect it strengthens the body. Due to the increased usage of nanomaterials in commercial products, their influence on living organisms cannot be neglected and therefore brings nowadays high scientific attention. Materials with at least one dimension less than 100 nm, called nanomaterials, exhibit different physical properties compared to bulk materials. The most often used nanomaterials include graphene and its derivatives, as well as exhibiting antimicrobial properties silver nanoparticles.

In the publication, R. Seyed Alian and co-authors demonstrate that house cricket (Acheta domesticus) food supplementation by nanoparticles (graphene oxide, silver nanoparticles and their composite) leads to the early stress response in crickets. Nanoparticles can modify the gut functions and change the energy budget of crickets, but the initial inhibition of energy assimilation is compensated afterwards simultaneously with increased activity of digestive enzymes. Even low amounts of nanoparticles can influence an early physiological response that stimulates cricket organisms and look like hormesis.

Therefore, despite the different harmful effects due to the nanoparticles, the exposed organisms mobilize their defence system.