Silver nanoparticles for antibacterial use: Extrinsic and intrinsic factors to increase stability

Recent studies with silver nanoparticles (AgNPs), a broad spectrum bactericidal and virucidal agent, place them as a promising ingredient in fighting the spread of multiresistant bacteria, viruses and neglected diseases, as well as other biological uses. In this review, we show the difference between the mechanisms of the AgNPs and silver ions (Ag+ ) in the chemical, biological and toxicological level, as well as the augmented influence of the bactericidal activity in the facets {111}. To better understand the efficacy of the AgNPs as an antimicrobial agent, the mechanism of action of the AgNPs was analyzed in bacteria and viruses. Furthermore, we described intrinsic and extrinsic factors that directly affect the physical-chemical stability of AgNPs and are essential for their biological use, in future clinical studies and in the development of new products containing AgNPs. (author)