Figure 1.

Calibration of osmolarity-sensitive liposomes. (A) G/R fluorescence ratio recorded over an interval of 500 s when liposomes prepared at 245 mOsm were suspended in swarm media at the osmolarities indicated on the plot. Note the minimal effect of fluorescence bleaching on the G/R ratio. (B) G/R ratios from liposomes that were loaded on agar surfaces 0.5 h before recording. Osmolarities of the swarm media used to prepare the plates were measured after the media and agar were separated by centrifugation. These values are shown on the plot. The dotted lines show the data after correction for photobleaching. The changes that remain are due to evaporation. (C) G/R ratios at medium osmolarities recorded between 300 and 350 s. (D) Comparison of the G/R ratios measured in suspension (red circles) and those measured on an agar surface (black diamonds) as a function of the osmolarity of the swarm media.