Role of Oxide Surface Chemistry and Phospholipid Phase on Adsorption and Self-Assembly: Isotherms and Atomic Force Microscopy

Abstract

We have examined the effects of metal oxide surface chemistry and lipid phase on phospholipid adsorption affinity and self-assembly. Adsorption isotherms of ditridecanoylphosphocholine (DTPC) at 40 °C and pH 7.2 on quartz (α-SiO2), rutile (α-TiO2), and corundum (α-Al2O3) particle suspensions indicated oxide-dependent adsorption affinity that decreased as rutile > corundum ≅ quartz at low concentrations and corundum > rutile ≅ quartz at higher concentrations. Significantly, atomic force microscopy of DTPC and dipalmitoylphosphocholine (DPPC) at high concentration on planar oxide surfaces at 25 °C in liquid-crystal and gel phases, respectively, also showed oxide-specific adsorption. Multiple bilayers formed on corundum (100), indicating greater coverage compared to single bilayers, bilayer patches, or supported vesicle layers on the negatively charged surfaces of mica (001), rutile (100), and amorphous silica glass (fused quartz plate). Thus, the amount and self-assembly of adsorbed phospholipid was found to be oxide-dependent regardless of the lipid phase. Significantly, both experimental methods show multiple bilayer formation as a unique feature of the positively charged alumina surface. The observed oxide affinity sequences are interpreted as controlled by van der Waals and electrostatic forces between the oxide surface and the negatively charged (−R(PO4 −)R′−) portion of the phosphocholine headgroup. Our results have implications for the interactions of amphiphilic molecules with mineral surfaces in diverse biogeochemical, biomedical, and industrial processes, including membrane-bound biomineralization, cell membrane stability during early evolution of life, organic matter burial in ocean sediments, the design of supported lipid bilayers and biomimetic cell membranes for medical implant devices, enhanced oil recovery, and ore extraction by froth flotation.

Interaction energies between oxide surfaces and multiple phosphatidylcholine bilayers from extended-DLVO theory

“…Furthermore, vesicle rupture and stability of stacked multiple bilayers on mineral surfaces may provide a model for evolution of pre-biotic, or early, cell membranes. Spontaneouslyformed and fabricated multiple SPBs on particles and planar surfaces of SiO 2 , TiO 2 , Al 2 O 3 , and mica have been reported previously [4,5,11,[13][14][15][16][17][18].…”

“…The diversity of current and potential applications for solid-supported phospholipid bilayers (SPBs) in areas such as biomedicine, biomineralization, biogeochemistry, materials science, and environmental remediation is established in the literature [1][2][3][4][5]. Efforts to produce and characterize SPBs have focused mainly on systems in which a single bilayer is deposited on the substrate.…”

Cell membrane disruption induced by amorphous silica nanoparticles in erythrocytes, lymphocytes, malignant melanocytes, and macrophages

“…It is noted that a major constituent of cell membranes is phosphatidylcholine (PC), which has a zwitterionic head group of the phosphate ester (ÀR(PO 4 À )R 0 À) and the quaternary amine (ÀN(CH 3 ) 3 + ) moieties and is more commonly found in the exoplasmic leaflet of a cell membrane. The interactions of silica particles with protein-free bilayers of PC have been investigated by the leakage of entrapped tracers from liposomes [56][57][58], the adsorption isotherms [57][58][59][60][61][62], the nuclear magnetic resonance (NMR) spectroscopy [63], the cryogenic transmission electron microscopy (Cryo-TEM) [64], the fluorescence microscopy and isothermal titration calorimetry [65], and the calorimetry, electrophoresis, dynamic light scattering (DLS), and Cryo-TEM [66,67]. The interactions of silica particles with supported membranes of PC have been studied by the electrochemistry and calorimetry [68] and the electrophysiology and fluorescence microscopy [69].…”

“…The interactions of silica particles with supported membranes of PC have been studied by the electrochemistry and calorimetry [68] and the electrophysiology and fluorescence microscopy [69]. In addition to the particulate silica, the interactions of silica substrates with PC liposomes [70] have been studied by quartz crystal microbalance (QCM) [71][72][73] and AFM [62,74]. These studies indicate that affinity of the bare silica surface for neutral PCs is rather weak and mainly attributed to van der Waals forces [58][59][60][61][62]68], which is consistent with the results of our AFM measurements shown in Fig.…”

Lipid-based Biomimetics in Drug and Vaccine Delivery

“…Glass microspheres coated with phospholipid layers evaluated the binding specificity of enzymes on cell surface (Obringer et al 1995) or quantified lipid-antibodies binding (Kiser et al, 1998). Recent work continues to investigate lipid-supporting particles based on minerals Nordlund et al 2009;Ahmed & Wunder, 2009;Xu et al, 2009;Oleson & Sahai, 2008;Pyiasena et al, 2008;Senarath-Yapa et al 2007;Moura & Carmona-Ribeiro, 2007;Parida et al, 2006), polymers Jha & Bose, 2009;Thevenot et al, 2008;Bershteyn et al 2008;Zuzzi et al, 2008;Troutier et al, 2005;Pereira et al, 2004), metals eg magnetoliposomes for biomedical applications or contrast agents in magnetic resonance imaging (Bulte & De Cuyper, 2003) or biological cells as templating cores to be dissolved to obtain capsules (Ge et al, 2003) or viruses for enhancing adenovirus tumor targeting in vivo (Singh et al, 2008). Polymer hollow capsules were produced by Möhwald and coworkers (Ge et al, 2003) from the polyelectrolyte layer-by-layer technique on biological cells.…”