Molecular dynamics of the interaction of anionic surfactants with liposomes

The time dependent molecular interactions of sodium dodecyl sulfate (SDS) with dipalmitoylphosphatidylcholine (DPPC) liposomes were studied using attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy. In particular, the ATR spectra provided information on the dynamic amount of SDS incorporated and DPPC expelled in the DPPC structure along with structural information on the molecular nature of the SDS/DPPC assemblies. It was found that the uptake of SDS was always mirrored by the ejection of DPPC molecules from the liposomes and that the incorporation of SDS followed two routes; SDS intercalated into the DPPC liposomes and SDS was bound electrostatically to the charged surface of the DPPC liposome.

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► In situ ATR-FTIR analysis of liposome–SDS interactions.
► Adsorption of SDS occurs through head-to-head and lateral-to-lateral interaction with DPPC molecules.
► Time dependent change in IR bands are used to identify point of liposome rupture.