3.7. Metal-induced antibacterial activity
E. coli DH5α and B. subtilis 168 were used as model species
to evaluate mass transfer from the clay to bacteria. The 24 hours of
incubation at 37 oC of untreated host matrices (NaMt,
BoltornTMH20 and H20@NaMt) with a population of
74.106 CFU.mL-1 revealed no
antibacterial activity in three independent experiments with bothE. coli and B. subtilis strains. For conciseness, only
data obtained with B. subtilis were mentioned herein
(Fig. 3.a) . In contrast, copper-loaded (Cu/NaMt) and
silver-loaded (Ag/NaMt) clays exhibited noticeable antibacterial
activity (Fig. 4) , demonstrating that clay minerals can behave
as MNP-hosting matrices. This improvement would be due to metal
incorporation (Gordon et al., 2010; Potera, 2012; Vincent, Duval,
Hartemann, & Engels‐Deutsch, 2018; Yun’an Qing et al., 2018) but the
mechanisms remain to be elucidated..