Improved effect of amikacin-loaded Poly (D, L-lactide-co-glycolide) (PLGA) nanoparticles against Planktonic and biofilm cells of Pseudomonas aeruginosa.

Amikacin is one of the most effective antibiotics against Pseudomonas aeruginosa infections but, according to its high toxicity, the use of this antibiotic has been clinically limited. In the present study, amikacin was successfully loaded into a new formulation of nanoparticles based on PLGA 50:50. Amikacin-loaded nanoparticles showed desirable antibacterial and antibiofilm characteristics. Flow cytometric studies showed that these nanoparticles were able to interact with Planktonic and biofilm bacterial cells. Moreover, following one hour of incubation of amikacin-loaded nanoparticles with one-day-old biofilm, it was found that particles penetrate through the whole biofilm thickness. Live/dead fluorescent staining followed by confocal laser scanning microscopy analysis showed that the amikacin-loaded nanoparticles were more effective than free drug in biofilm eradication. Association of fluorescently labeled amikacin-loaded nanoparticles with mouse monocyte macrophage cells (RAW 264.7) was assessed by flow cytometry and confocal microscopy. It was shown that 75% of the cells were able to uptake the nanoparticles after 2 h of incubation at 37 °C. The proper antibacterial and antibiofilm activity of amikacin-loaded nanoparticles in addition to their ability to enter macrophages without any cytotoxicity for these cells make them a potential candidate to treat P. aeruginosa infections.