  The use of nanoparticles for intracellular drug delivery could reduce the
toxicity and side effects of the drug but, the uptake of these nanocarriers
could induce adverse effects on cells and tissues after their incorporation.
Macrophages play a central role in host defense and are responsible for in vivo
nanoparticle trafficking. Assessment of their defense capacity against
pathogenic micro-organisms after nanoparticle uptake, is necessary to prevent
infections associated with nanoparticle therapies. In this study, the effects
of hollow mesoporous SiO2-CaO nanospheres labeled with fluorescein
isothiocyanate (FITC-NanoMBGs) on the function of peritoneal macrophages was
assessed by measuring their ability to phagocytize Candida albicans expressing
a red fluorescent protein. Two macrophage-fungus ratios (MOI 1 and MOI 5) were
used and two experimental strategies were carried out: a) pretreatment of
macrophages with FITC-NanoMBGs and subsequent fungal infection; b) competition
assays after simultaneous addition of fungus and nanospheres. Macrophage
pro-inflammatory phenotype markers (CD80 expression and interleukin 6
secretion) were also evaluated. Significant decreases of CD80+ macrophage
percentage and interleukin 6 secretion were observed after 30 min, indicating
that the simultaneous incorporation of NanoMBG and fungus favors the macrophage
noninflammatory phenotype. The present study evidences that the uptake of these
nanospheres in all the studied conditions does not alter the macrophage
function. Moreover, intracellular FITCNanoMBGs induce a transitory increase of
the fungal phagocytosis by macrophages at MOI 1 and after a short time of
interaction. In the competition assays, as the intracellular fungus quantity
increased, the intracellular FITC-NanoMBG content decreased in a MOI- and
timedependent manner...
