Effects of bilayer surface charge density on molecular adsorption and transport across liposome bilayers

Second harmonic generation (SHG) was used to study both the adsorption of m alachite green (MG), a positively charged organic dye, onto liposomes of di fferent lipid compositions, and the transport kinetics of MG across the lip osome bilayer in real time. We found that the dye adsorption increased line arly with the fraction of negatively charged lipids in the bilayer. Similar ly, the transport rate constant for crossing the bilayer increased linearly with the fraction of charged lipid in the bilayer.