Enhanced bactericidal activity of brucite through partial copper substitution

Abstract

Copper substituted Mg(OH)2 nanoplatelets exhibit high bactericidal activity towards S. aureus and E. coli with fast kinetics.

Understanding the bactericidal mechanism of Cu(OH)2 nanorods in water through Mg-substitution: high production of toxic hydroxyl radicals by non-soluble particles

“…Table S2 in ESI† displays the results. As we previously showed, 37 Mg(OH) 2 nanoparticles have poorly bactericidal performances in the evaluation conditions we used. Its presence as secondary phase in the Cu 0.85 Mg 0.15 (OH) 2 and Cu 0.80 Mg 0.20 (OH) 2 samples only further increases the slowing down of the bactericidal kinetics of the mixed hydroxides.…”

“…1). In our previous study, 37 TG-MS evolved gas analyses showed that nanoplatelets of Mg(OH) 2 starts decomposing above 300 °C by releasing water molecules (peak at 350 °C in the m / z = 18 spectrum). The step in the tail of the TG curve of the Cu 0.8 Mg 0.2 (OH) 2 sample is therefore ascribed to the thermal decomposition of this secondary phase Mg(OH) 2 .…”

“…1b) which is ascribed to the presence of the secondary phase Mg(OH) 2 . 37 In the crystal structure of Cu(OH) 2 , 32 cupric ions are 5-fold coordinated to hydroxide ions, thus forming pyramids [Cu(OH) 5 ] 3 − (Fig. 1c).…”

“…This assumption is consistent with the difference between the reductions in viability of E. coli (100% or >6 log 10 reduction) and S. aureus (99% or 2 log 10 reduction) we observed after 180 min in contact with the platelet-like “Mg 0.85 Cu 0.15 (OH) 2 ” nanoparticles at pH ≈ 10.4. 37…”

“…This assumption is consistent with the difference between the reductions in viability of E. coli (100% or 46 log 10 reduction) and S. aureus (99% or 2 log 10 reduction) we observed after 180 min in contact with the platelet-like ''Mg 0.85 Cu 0.15 (OH) 2 '' nanoparticles at pH E 10.4. 37 Only E0.06 and E0.4 wt% of the Cu(OH) 2 nanorods dissolve in water after 180 min and 1440 min, respectively (Table 2). As we expected, the incorporation of 10 mol% Mg 2+ in the cationic sub-lattice of Cu(OH) 2 enhances the dissolution of nanorods in water by 5.5-fold increase the concentration in cupric ions released after 180 min.…”