Abstract
The antibacterial properties of nanomaterials are well-known and have been extensively studied. On the other hand, bacterial responses to these structures are largely unknown. Notably, defense mechanisms that stimulate physiological features are frequently omitted. Studies on these effects indicate that nanomaterials may stimulate the production of primary and secondary metabolites. The stimulation effects range from cell agglomeration to the secretion of pigments. Contact with nanostructures changes the expression of genes responsible for responding to reactive oxygen species, efflux pumps, and virulence factors. These findings can be potentially used in biotechnology and bioprocess engineering, using nanostructures as stimulants for the biological production of valuable metabolites. On the other hand, the potential stimulation of virulence factors or the risk associated with increased transfer of antibiotic resistance may limit the use of nanomaterials in medical devices that have direct contact with patients. In that manner, more transcriptomic and metabolomic studies are necessary to fully assess the stimulative potential of nanomaterials in biotechnology and medicine.