Biophys J, August 2002, p. 954-967, Vol. 83, No. 2

Interactions of Adriamycin, Cytochrome c, and Serum Albumin with Lipid Monolayers Containing Poly(ethylene glycol)-Ceramide

Helsinki Biophysics and Biomembrane Group, Institute of Biomedicine, University of Helsinki, FIN-00014 Helsinki, Finland

Poly(ethylene glycol)₂₀₀₀C₂₀ceramide (PEG-Cer) containing monolayers at an air/water interface were characterized by measuring their surface pressure versus area/molecule (-A) and surface potential versus area/molecule (V-A) isotherms. The behavior of -A as well as V versus lipid density (V-n) and V- isotherms for PEG-Cer are in keeping with two transitions of the lipopolymer, starting at   9 and 21 mN/m. We also investigated the effects of PEG-Cer on the binding of adriamycin, cytochrome c and bovine serum albumin to monolayers containing varying mole fractions X of PEG-Cer. PEG-Cer impedes the penetration of these ligands into lipid monolayers with similar effects at both X = 0.04 and 0.08. This effect of PEG-Cer depends on the conformation of the lipopolymer and the interactions between the lipid surface and the surface-interacting molecule as well as the size of the latter.

Biophys J, August 2002, p. 954-967, Vol. 83, No. 2
© 2002 by the Biophysical Society   0006-3495/02/08/954/14  $2.00