Positioning and alignment of lipid tubules on patterned Au substrates.

This paper presents a method for positioning and aligning self-assembled tubules of 1,2-bis(tricosa-10,12-diynoyl)-sn-glycero-3-phosphochloline (DC(8,9)PC) by withdrawing a patterned Au substrate from tubule solution. The patterned Au substrates with alternating bare Au stripes and thiol monolayer stripes are formed by microcontact printing. We find that the lipid tubules selectively adsorb on the bare Au stripes but show no orientation order. By withdrawing the patterned Au substrates at the direction along the stripes from tubule solution, the lipid tubules are found to be aligned along the direction of the Au stripes. The angular distribution and the density of the aligned lipid tubules depend on the withdrawal rates and the adsorption time, respectively. We conclude that forces causing tubule alignment that originate in the surface tension associated with the moving meniscus dominate alignment forces exerted by the patterned Au substrates.