Examination of the biological activity of poly(D,L-Lactic-co-glycolic acid) encapsulated juglone nanoparticles

In this thesis, nanoparticulate systems were prepared by encapsulating juglone molecule, a secondary metabolite with antimicrobial activity, into poly(D,L-lactic-co-glycolic acid) (PLGA) by single emulsion solvent evaporation method and then characterized. The effect of the produced nanoparticles on Candida albicans biofilm was investigated in comparison with free juglone by performing XTT, crystal violet, standard plate count, confocal microscopy and membrane depolarization analyzes. As a result; juglone, an orange-brown dye, was found to cause deviations in the results of XTT and crystal violet analyzes. Significant and consistent results were obtained in the standard plate count and confocal microscopy studies. Juglone encapsulated PLGA nanoparticulate systems and free juglone were found to inhibit the formation of C. albicans biofilm and pre-formed 6-hour biofilms (98-100%) at all doses applied. Furthermore, membrane depolarization analysis showed that juglone and juglone-PLGA nanoparticles were effective on C. albicans membrane structure. It is extremely important that the antibiofilm effect of the juglone-PLGA nanoparticles is similar to that of the juglone used at the same concentration, since similar effect is provided by using less active substance due to controlled release and the PLGA nanoparticulate system reduces toxicity according to the literature. Additionally, this work may be a useful model for investigating the effect of other antimicrobial agents on biofilm.