Poly(lactic-co-glycolic) acid nanoparticles localize in vesicles after diffusing into cells and are retained by intracellular traffic modulators.

Aim: We investigated our previous finding of increased retention of poly(lactic-co-glycolic) acid nanoparticles (PLGA-NPs) with metabolic inhibitors (MI) and studied the effect of some small molecule inhibitors on PLGA-NP assimilation. Materials & methods: Intracellular PLGA-NP colocalization in the presence of MI was investigated by confocal microscopy. Intracellular retention of PLGA-NPs by some small molecules was estimated by fluorescence microscopy and flow cytometry after Pulse/Chase experiments. Results: MI caused PLGA-NP colocalization in intracellular membranous structures, mainly endosomes and lysosomes. Some small molecule inhibitors demonstrated increased intracellular PLGA-NP accumulation. Conclusion: This study elucidates the movement of PLGA-NP in cells and suggests that clinically used small molecules can reduce their extrusion by enhancing their stay within intracellular vesicles, with possible clinically beneficial consequences.