Liposome destabilization by a 2,7-diazapyrenium derivative through formation of transient pores in the lipid bilayer.

The effect of the luminescent heteroaromatic electron acceptor N,N'-dimethyl-2,7-diazapyrenium dichloride (DM-DAP(2+)) on the stability of 1-palmitoyl-2-oleoylphosphatydilcholine (POPC) liposomes is determined on the basis of the rate of release of different fluorescent probes entrapped within the liposome. The experiments show that DM-DAP(2+) exerts a substantial destabilizing action on the liposomal bilayer, particularly at low concentrations. Molecular dynamics simulations suggest that the activity of DM-DAP(2+) is related to its tendency to surround itself with water molecules, conceivably favoring the formation of transient pores across the bilayer.