PLGA micro or nanoparticles differently induce inflammatory response in murine macrophages

Many studies have discussed the ideal size of PLGA particles in contributing to the generation of the different types of immune response. However, these studies do not demonstrate the effect of micro or nanoparticles, without any encapsulated bioactive, on phagocytic cells after the uptake process. In this context, the aim of this study was to analyze the in vitro inflammatory behavior of J774 murine “macrophage-like” cells after particles' uptake, since nano/microparticles per se can differently activate phagocytic cells, using or not appropriate receptors, inducing distinct inflammatory responses. An o/w emulsion solvent extraction–evaporation method was chosen to prepare the particles. We determined their diameters, zeta potential and morphology. Fluorescent particles' uptake by J774 cells was also analyzed. To evaluate the in vitro inflammatory profile of these cells after micro or nanoparticles' uptake, we conducted NF-κB translocation assay by confocal microscopy and also determined the pro-inflammatory cytokines production provoked by the particles.