RESUMO
Halogenated dodecaborates, and especially dodecaiodododecaborate(2-), are found to trigger effectively the release of the contents of phospholipid liposomes, including liposomes containing distearoylphosphatidylcholine and cholesterol, which are used clinically in cancer therapy. The basis of the release is studied through differential scanning calorimetry, cryo-transmission electron microscopy, and atomic force microscopy. Upon administration at high concentrations, drastic morphological changes are induced by the dodecaborates. Their possible use in triggered release is suggested.
RESUMO
BACKGROUND: Combinations of trypan blue (TB), Brilliant Blue G (BBG) and polyethyleneglycol had been shown before to be less toxic to ARPE retinal pigment epithelial cells than TB alone. We studied systematically the influence of combinations of dyes on cell damage. METHODS: ARPE cells were exposed to TB (concentration range 0.025 to 1 %), BBG (0.0025 to 0.5 %), and combinations of the two dyes, dissolved in phosphate buffered saline (PBS), for periods between 5 and 60 min. Cell damage was monitored with the WST-1 assay. The effect of different salt concentration was measured in the same way. RESULTS: TB in concentrations of 0.075 % and higher was toxic to the cells already after 30 min incubation. BBG was toxic after 30 min in concentration of 0.1 % and higher, but had a protective effect on cells with incubation time of 5 min and concentrations up to 0.1 %. BBG at concentrations of 0.025 % protected against TB-induced damage at 5 min and 30 min incubation. Salt concentrations between 113 and 225 mM did not influence cell survival even after 30 min. In the presence of TB, propidium iodide bound strongly to the cells. CONCLUSIONS: BBG acts as a protecting agent against TB toxicity.
