Liposome-modified glassy carbon

Since Upids are known to associate with DNA with high affinity, the adsorption of ssDNA at lipid membranes as a medium for DNA incorporation on a GC surface was extensively studied [60]. Exploiting DNA-Upid interactions, various approaches were designed for the incorporation of ssDNA [61] and dsDNA [62] at a modified bilayer lipid membrane (BLM) GC surface, such as (1) the formation of self-assembled BLMs over ssDNA previously adsorbed on GC, (2) the direct adsorption of ss- and dsDNA [62] into a previously BLM-modified GC and, (3) formation of a BLM with incorporated ssDNA at the GC surface using the monolayer folding technique [61]. 

The ssDNA was immobilized stronger and faster on the GC surface in the presence of the lipid membrane than on a bare GC surface and using milder conditions [61]. The lipid membrane enhanced the stabihty of ssDNA towards desorption from the GC surface [61,62]. Moreover, the adsorption of ssDNA on BLM induced a conductance enhancement due to (1) structural changes (i.e., defect sites) within the membrane and (2) the increase in negative surface charge density of the membrane. The charge of the phosphate groups of ssDNA induced an increase of cation concentration in the electrical double layer [63]. 

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Electrochemistry may also be used to probe the interactions between ferrocifens and nonpolar molecular architectures, with respect to the hydrophobic architectures/barriers that compose ceU membranes as well as lipidic cargoes/vectors (e.g., liposomes) using model systems consisting of glassy carbon electrodes modified with a planar bilayer of 1,2-dimyristoyl-OT-glycero-3-phosphocholine (DMPC) (Fig. 47.20) [56]. 

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