However, it will require further efforts to elucidate whether the antibacterial effect of AgNPs, particularly those below
10 nm, is entirely driven by direct cell–AgNP contact or by the release of Ag+ ions which could also play an important role.
Perhaps an initial AgNP bacterial contact may trigger the principal antibacterial mechanism by facilitating the entry of
AgNPs inside the bacterial cells followed by a burst release of silver ions inside the bacterial cells just sufficient to cause the bactericidal effect. Therefore, the hypothesis of a synergistic mechanism between contact killing and silver release should not be overlooked. Further studies are needed to explore the above possibilities.