FIG 5.

Treatment with Au-conjugated chlorhexidine nanoparticles abolished A. castellanii-mediated HBMEC cytotoxicity. Briefly, amoebae (5 × 10⁵ amoebae/0.5 ml/well) were incubated with different concentrations of Au-conjugated chlorhexidine nanoparticles and chlorhexidine alone for 24 h in RPMI and then incubated with HBMEC for 18 h at 37°C in a 5% CO₂ incubator as described in Materials and Methods. The next day, cell-free supernatant was collected and cytotoxicity was determined. The results revealed that pretreatment with Au-conjugated chlorhexidine nanoparticles at 5 μM concentration, but not chlorhexidine alone at 5 μM concentration, abolished A. castellanii-mediated HBMEC cytotoxicity. The results are expressed as the means ± standard errors from three independent experiments performed in duplicate.