title: Oxidative Damage to Biomimetic Membrane Systems: In Situ Fe(II)/Ascorbate Initiated Oxidation and Incorporation of Synthetic Oxidized Phospholipids.
abstract: Damage to cellular membranes from oxidative stress has been implicated in aging related diseases. We report the effects of oxidative damage on the structure and properties of biomimetic phospholipid membrane systems. Two oxidation methods were used, in situ oxidation initiated using Fe(II) and ascorbate, and the incorporation of a synthetic "oxidized" phospholipid, PoxnoPC, into biomimetic membranes. The biomimetic systems employed included multibilayer stacks, tethered bilayers, and phospholipid monolayers studied using a combination of reflectometry, attenuated total reflection infrared spectroscopy, electrochemical impedance spectroscopy, and neutron diffraction. We show that oxidation with Fe(II) and ascorbate caused an increase in the order of the membrane, attributed to cross-linking of the phospholipids, and a change in the electrical permeability of the membrane, but no significant impact on the thickness or completeness of the membrane. Incorporation of PoxnoPC, on the other hand, had a larger impact on the structure of the membrane. Inversion of the aldehyde-terminated truncated sn-2 chain of PoxnoPC into the head group region was observed, along with a slight decrease in the thickness and order of the membrane.
authors.affiliation: School of Chemical Sciences, The University of Auckland , Private Bag 92019, Auckland 1142, New Zealand.
authors.forename: Jacqueline J
authors.initials: JJ
authors.lastname: Knobloch
authors.affiliation: Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232, Australia.
authors.forename: Andrew R J
authors.initials: AR
authors.lastname: Nelson
authors.affiliation: Centre for Nanoscale Science and Technology, School of Chemical and Physical Sciences, Flinders University , GPO 2100, Adelaide 5001, Australia.
authors.forename: Ingo
authors.initials: I
authors.lastname: Köper
authors.affiliation: Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232, Australia.|Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168, Australia.
authors.forename: Michael
authors.initials: M
authors.lastname: James
authors.affiliation: School of Chemical Sciences, The University of Auckland , Private Bag 92019, Auckland 1142, New Zealand.|MacDiarmid Institute for Advanced Materials and Nanotechnology, P.O. Box 600, Wellington 6140, New Zealand.
authors.forename: Duncan J
authors.initials: DJ
authors.lastname: McGillivray
mesh_terms: D001205:Ascorbic Acid / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D008567:Membranes, Artificial; D010084:Oxidation-Reduction; D010743:Phospholipids / Q000737:chemistry*
chemical_list: D008567:Membranes, Artificial; D010743:Phospholipids; D007501:Iron; D001205:Ascorbic Acid