Fig. 5 ROS generation (A, B) and SEM pictures (C) of bacteria after
treatments with bactericidal agents.
Based on the comprehensive results discussed earlier, it is evident that
R12-AgNPs exhibit a synergistic antibacterial effect when combined with
H2O2. The proposed mechanism for
bacterial inhibition may involve the following steps (Fig. 6): (1)
R12-AgNPs capture and adhere to the negatively charged bacterial
surfaces through electrostatic attraction; (2) R12-AgNPs facilitate the
sustained release of Ag+ ions in the vicinity of the
bacteria. These released Ag+ ions can interact with
thiol groups found in critical proteins within the bacterial cells. As a
result, many essential enzyme proteins may become inactivated [52];
(3) R12-AgNPs possess peroxidase-like activity, which allows them to
catalyze the decomposition of H2O2,
yielding a substantial quantity of hydroxyl radicals. These hydroxyl
radicals act on biofilms, lipids, proteins, and DNA, leading to the
degradation and disruption of these critical structures within the
bacterial cells. Ultimately, this process results in bacterial death
[53]. The antibacterial mechanism of R12-AgNPs in combination with
H2O2 involves multiple synergistic
steps, which collectively lead to the effective inhibition and
destruction of bacterial cells.