Biocompatibility and Biodistribution of amoxicillin coated gold nanoparticles effective against antibiotic-resistant bacteria

Buenos Aires

Congreso; . Reunión Conjunta de Sociedades de Biociencias; 2017

Gold nanoparticles synthesized and stabilized with amoxicillin (amoxi@AuNP) have shown, in our previous experiments, to be bactericidal when irradiated with a LED panel. Their use in Photodynamic Therapy is very promising because they were effective even in antibiotic-resistant strains. The goal of this work was to evaluate their effect on eukaryotic cells and their biodistribution, under the same conditions in which they produced the photothermic effect: 1.5 μg / mL, 30 minutes of irradiation. In vitro experiments have proven that amoxi@AuNP did not produce significant hemolysis nor reduce fibroblast viability, according to the MTT assay, even after 24 hours. In addition, amoxi@AuNP completely killed prokaryotic cells, without affecting eukaryotic cells integrity. This was observed through a novel methodology using Fluorescence Lifetime Imaging System developed to study co-cultures of fresh blood cells with bacteria. On the other hand, TEM images of fixed tissue samples from male Wistar rats administered with amoxi@AuNP showed that most of them were found in the kidneys (samples 2 hours post intraperitoneal injection), after internalization through the microvilli and subsequent degradation in vesicles. They were also present in smaller amounts inside phagocytic cells in the liver and the spleen, but did not pass through brain blood barrier. Although 5% of the nuclei showed pyknosis 5 hours after administration, all tissues recovered normal structures the next day. This findings and spectrophotometrically analized urine samples collected along 24 hours, indicate that they are rapidly eliminated from the body, mainly by renal clearance. Overall, the amoxi@AuNP seem to be non-toxic to mammals cells in their bactericidal conditions.