Eur. Phys. J. B 6, 1-4 (1998)
https://doi.org/10.1007/s100510050519

Translational order in liquid-expanded lipid monolayers functionalized with nucleosides

¹ Laboratoire de Physique Statistique de l'École Normale Supérieure (Laboratoire associé au CNRS et aux Universités Paris VI et Paris VII.) , 24 rue Lhomond, 75231 Paris Cedex 05, France
² Physico-Chimie Curie, 11 rue Pierre et Marie Curie, 75231 Paris, France
³ Laboratoire pour l'Utilisation du Rayonnement Électromagnétique, Université Paris Sud, 91405 Orsay, France
⁴ Laboratoire de Synthèse Bio-Organique (CNRS, UMR 7514) , Faculté de Pharmacie, 74 route du Rhin, 67401 Illkirch, France

Corresponding author: ^a perez@physique.ens.fr

Received: 3 August 1998
Revised: 16 September 1998
Accepted: 21 September 1998
Published online: 15 November 1998

Abstract

The monolayer behavior of a lipid containing two unsaturated alkyl chains and a nucleoside derivative as polar headgroup has been investigated by the Langmuir technique. From the surface pressure vs. molecular area isotherm, the monolayer appears as a pure liquid-expanded phase and should be then considered as a two-dimensional liquid. However, grazing incidence X-ray diffraction experiments evidence a translational order that does not exist when the lipid headgroup is a choline moiety. Since unsaturated chains are expected to induce a fluid state of the monolayer at the temperature considered, this order is likely to originate from the natural tendency nucleosides have to establish among themselves π-stacking interactions between the bases. The collected X-ray data are consistent with the geometrical requirements for bases stacking.