Nanomaterials have become part of our daily lives, particularly nanoparticles contained
in food, water, cosmetics, additives and textiles. Nanoparticles interact with organisms
at the cellular level. The cell membrane is the first protective barrier against the potential toxic
effect of nanoparticles. This first contact, including the interaction between the cell membranes
-and associated proteins- and the nanoparticles is critically reviewed here. Nanoparticles, depending
on their toxicity, can cause cellular physiology alterations, such as a disruption in cell
signaling or changes in gene expression and they can trigger immune responses and even apoptosis.
Additionally, the fundamental thermodynamics behind the nanoparticle-membrane and
nanoparticle-proteins-membrane interactions are discussed. The analysis is intended to increase
our insight into the mechanisms involved in these interactions. Finally, consequences are reviewed
and discussed.