Surface-dependent endocytosis of poly(isobutylcyanoacrylate) nanoparticles by Trichomonas vaginalis.

Previous data from our research group showed that chitosan-coated poly(isobutylcyanoacrylate) nanoparticles (NPs) (denoted PIBCA/Chito20) exhibited intrinsic anti-Trichomonas vaginalis activity, while PIBCA/pluronic® F68 without chitosan (PIBCA/F68) were inactive. However, the mechanism of anti-T. vaginalis activity of chitosan-coated PIBCA NPs is still unknown. Our hypothesis is that chitosan-coated NPs are internalized by the parasite, contrarily to PIBCA/F68. In this investigation, the impact of NP surface on their internalization by the protozoan was studied using flow cytometry and parasite morphological changes after different incubation times with PIBCA/Chito20 NPs were monitored by electron microscopy. Flow-cytometry revealed that PIBCA/Chito20 NPs were uptaken by T. vaginalis as early as 10-min-incubation. Drastic cell morphological transformations were observed from scanning electron microscopy and transmission electron microscopy after incubation with PIBCA/Chito20 NPs. Numerous pits were seen on cell membrane since 10 min. Gradual increase in contact time increased NP endocytosis and induced proportional damages to T. vaginalis membrane. Then, investigation of whether PIBCA/Chito20 NPs can improve MTZ anti-T. vaginalis activity was studied using checkerboard experiment. Calculation of fractional inhibitory concentration index (FICI = 3.53) showed an additive effect between NPs and MTZ.

Role of divalent cations, pH, cytoskeleton components and surface charge on the adhesion of Trichomonas vaginalis to a polystyrene substrate.

The process of adhesion of three different strains of Trichomonas vaginalis to a polystyrene substrate was analysed. The process of adhesion was dependent on the time of incubation and the pH of the phosphate-buffered solution (PBS) in which the parasites were suspended. The highest indices of adhesion were observed after an incubation time of 60 min at pH 6.6. The adhesion index increased when the parasites were incubated in the presence of culture media or when Ca++ or Mg++ was added to the PBS solution, whereas cytochalasin B, trypsin or neuraminidase reduced adhesion. Incubation of the parasites in the presence of poly-L-lysine facilitated the process of adhesion. Incubation of the parasites or polystyrene beads in the presence of poly-L-lysine led to important changes in their surface charge.