Disruption of cell membranes that are composed of lipid bilayers leads to dramatic biological effects. For example, pore-forming cytotoxins disrupt the cell membrane permeability causing the release of inflammatory cytokines and tissue damage. The Lipid Bilayer Permeability Disruption Assay employs a liposome-encapsulated dye to monitor the release of the dye due to damage of the integrity of the lipid bilayer. Since liposomes have the bilayer structure similar to cell membranes, this dye-releasing assay may be used to test compounds that disrupt the permeability and damage cell membranes. The released dye is monitored by fluorescence at 580 nm (excitation at 540 nm). It is a high throughput assay using 96-well plates and is suitable for screening of compound collections.
The liposome bilayer is composed of lipids HSPC: cholesterol: DSPE-PEG2000 (3:1:1 mass ratio) which is the same as the lipids for an existing liposomal drug in clinic. The dye is rhodamine conjugated with diethylenetriamine and its fluorescence is quenched inside of the liposome. When the bilayer permeability is disrupted, the encapsulated dye is released and the fluorescence is generated in the presence of the color development agent outside of the liposome.
The Lipid Bilayer Permeability Disruption Assay Kit (Catalog number BPD100K) includes 1.25 ml of liposomal dye, 1.25 ml of color development solution, 7.5 ml of buffer and 1 ml of DMSO. It is for assays of 100 samples using a 96-well plate.