INTRACELLULAR UPTAKE STUDY OF POLYMERIC NANOPARTICLES LOADED WITH CARDIOVASCULAR DRUGS USING CONFOCAL LASER SCANNING MICROSCOPY

Confocal laser scanning microscopy (CSLM) is a powerful microscopic tool that gives valuable morphological and functional information within cells and tissues. CLSM is non-invasive, with high-contrast scanning, a simple and fast sample preparation procedure as well as easy operation. The aim of this paper was to study the intracellular uptake of polymeric nanoparticles loaded with cardiovascular drugs using confocal laser scanning microscopy. Polymeric nanoparticles were prepared via nanoprecipitation method using poly(lactide-co-glycolide) (PLGA) as biodegradable polymeric matrix and Pluronic F127 as a stabilizer. A mixture of two cardiovascular drugs - valsartan (an angiotensin II receptor antagonist drug) and amlodipine besylate (a calcium channel blocker) - was loaded in polymeric nanoparticles. The prepared polymeric nanoparticles had sizes lower than 300 nm and narrow dispersity. The cellular uptake of polymeric nanoparticles was investigated by incubating adherent mouse embryo fibroblasts (NIH 3T3) with a suspension of nanoparticles (stained previously with phthalocyanine) at three different time points. Targeted cell compartments were labeled with two fluorophores: Rhodamine B (membrane stain) and Hoechst (nucleic acid stain). Live cell imaging was performed using a confocal microscope Zeiss LSM710 with Zeiss PALM microdissection system. The intracellular uptake of polymeric nanoparticles was revealed by confocal laser scanning microscopy for each incubation time. The results suggest a possible mechanism of endocytosis and clearly a vesicular-based accumulation of the nanoparticles in the cytoplasmatic compartments .