Ge. Fanucci et al., Multiple bilayer dipalmitoylphosphatidylserine LB films stabilized with transition metal ions, LANGMUIR, 17(5), 2001, pp. 1660-1665
Langmuir-Blodgett films of dipalmitoyl-DL-alpha -phosphatidyl-L-serine (DPP
S) have been transferred from aqueous subphases containing the 0.1 mM trans
ition metal compounds K2PdCl4, K2PtCl4, K2Pt(CN)(4), KAuCl4, and Cd[ClO4](2
). This report provides a detailed description of the formation and structu
ral characterization of the multiple bilayer films of DPPS that are formed.
The films were characterized through a combination of attenuated total ref
lectance Fourier transform infrared spectroscopy, X-ray diffraction, X-ray
photoelectron spectroscopy, and solid-state P-31 NMR. The results show that
the films are layered, there are two types of DPPS molecule in the films,
and the metals are incorporated as positive ions that bridge phospholipids
by complexing amines of the serine headgroups. Water molecules likely occup
y the remaining coordination sites of the metal complexes, leading to a pro
posed stoichiometry of [Pt(DPPS-)(2)(OH2)(2)](DPPS)(4). The metal ions stab
ilize film formation by screening repulsive interactions between the serine
headgroups through the formation of coordinate covalent bonds.