Adhesion of PLGA or Eudragit/PLGA nanoparticles to Staphylococcus and Pseudomonas

The aim of present study was to examine whether cationic Eudragit containing poly(lactide-co-glycolide) (PLGA) nanoparticles can adhere to Pseudomonas aeruginosa and Staphylococcus aureus. In order to prepare fluorescent nanoparticles, fluorescein was covalently coupled to PLGA. Fluorescent PLGA and Eudragit/PLGA nanoparticles were prepared by w/o/w emulsification solvent evaporation. Particle size and zeta potential of the nanoparticles were measured. Nanoparticles were incubated for a short time with P. aeruginosa and S. aureus followed by measurement of the size of nanoparticles and of P. aeruginosa and S. aureus with and without adherent nanoparticles. Flow cytometric measurements were performed to detect the attachment of particles to microorganisms. Eudragit containing nanoparticles possessed a positive zeta potential, while PLGA nanoparticles were negatively charged. Following adsorption of Eudragit containing nanoparticles, a size increase for P. aeruginosa was observed. Flow cytometric analyses confirmed that Eudragit containing particles showed stronger interactions with the test organisms than PLGA nanoparticles. Adhesion of particles was more pronounced for P. aeruginosa than for S. aureus. Cationic Eudragit containing nanoparticles showed better adhesion to microorganisms than anionic PLGA nanoparticles, which is probably due to enhanced electrostatic interactions.