tendency to agglomeration/aggregation of the particles. The
morphological features of the samples after calcination at 800 C/
1 h are unchanged.
The average particle size value was found to be in the range
3e7 nm for samples S4, S6. The variation of the magnetization with
the applied field (H) shows the existence of superparamagnetic
behavior. For the samples calcined 1 h at 800 C (S4-800, S6-800)
an average particle size values of 20.45 nm and 17.21 nm, respectively
were estimated from SEM (in good agreement with the
average crystallite size values of 187 Å and 168 Å, respectively
calculated based on XRD data). The remanence and the coercivity
increased after heat treatment, due to the increase in particle size
from SP size (monodomain) to the multi-domains size of cobalt
ferrite nanoparticles. The values of saturation magnetization of the
samples calcined at 800 C/1 h range between 42.8 and 72.3 emu/g
which are smaller than the bulk value for CoFe2O4, due to the
nanosized cobalt ferrites.
The antimicrobial, anti-biofilm and cytotoxic properties of
CoFe2O4 by wet ferritization route were evaluated. The results of
the antimicrobial activity revealed that tested cobalt ferrites have
generally exhibited good microbicidal and anti-biofilm features,
the most active combinations being S6-800 against planktonic
strains and S6 against biofilm embedded cells. The anti-biofilm
activity was manifested at both high and low concentrations,
and in certain cases lower than the MIC values recorded for the
same compounds, suggesting their potential use as antipathogenic
agents, defined as compounds which do not interfere
with the microbial growth, but could be able to inhibit the
m