Phospholipid-silica interfaces

The second selected example to illustrate the combined VASP/solid-state NMR/GIPAW approach is the characterization of the phospholipid/silica interface in silica-coated liposomes [29]. In such a system, one can distinguish two families of phosphate sites present in the lipid bilayer inner sites in interaction... 

Figure 20.5 Investigation of the phospholipid-silica interfaces by H- Si- H double cross-polarization, (a) TEM image of the liposome-silica nanocomposites with a schematic view of the structure, (b) Principle of the double CP NMR sequence, (c) Results of the...

Monolayers are best formed from water-insoluble molecules. This is expressed well by the title of Gaines s classic book Insoluble Monolayers at Liquid-Gas Interfaces [104]. Carboxylic acids (7-13 in Table 1, for example), sulfates, quaternary ammonium salts, alcohols, amides, and nitriles with carbon chains of 12 or longer meet this requirement well. Similarly, well-behaved monolayers have been formed from naturally occurring phospholipids (14-17 in Table 1, for example), as well as from their synthetic analogs (18,19 in Table 1, for example). More recently, polymerizable surfactants (1-4, 20, 21 in Table 1, for example) [55, 68, 72, 121], preformed polymers [68, 70, 72,122-127], liquid crystalline polymers [128], buckyballs [129, 130], gramicidin [131], and even silica beads [132] have been demonstrated to undergo monolayer formation on aqueous solutions. 

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