Ionic binding of phospholipids to interfaces: dependence on metal ion identity.
We report on the deposition of 1,2-dimyristoyl-sn-glycero-3-phosphatidic acid (DMPA) on selected metal-phosphate-terminated self-assembled monolayers (SAMs) constructed on Au. The phosphate-terminated SAMs were reacted with Zr(4+), Cu(+), Cu(2+), Fe(3+), Zn(2+), Ni(2+), Ca(2+), and Mg(2+), with subsequent exposure of the resulting interface to DMPA unilamellar vesicles. The resulting interface was characterized using X-ray photoelectron spectroscopy (XPS), optical ellipsometry, water contact angle measurements, and cyclic voltammetry (CV). The strongest lipid-metal ion interfacial interactions are with Zr(4+) and Fe(3+), with Ca(2+), Cu(+), Ni(2+), Zn(2+), and Mg(2+) producing somewhat less well organized adlayers. Cu(2+) did not bind strongly to the interfacial phosphate moiety, yielding a lipid bilayer structure. These results can be understood in the context of the strength of the metal bisphosphate complex that forms between the phospholipid and the chemically modified interface.
Oberts
B P
BP
Michigan State University, Department of Chemistry, East Lansing, Michigan 48824-1322, USA.
Blanchard
G J
GJ
D008051:Lipid Bilayers / Q000737:chemistry; D008670:Metals / Q000737:chemistry*; D008956:Models, Chemical; D010743:Phospholipids / Q000737:chemistry*; D056951:Photoelectron Spectroscopy
D008051:Lipid Bilayers; D008670:Metals; D010743:Phospholipids