Toward the rational control of nanoscale structures using chiral self-assembly: Diacetylenic phosphocholines

Results reported in this study provide, for the first time, a simple approach to tune the diameter of nanoscale diacetylenic phospholipid-based tubules. We have found a clear correlation between the n segments of the acyl chains in diacetylenic phosphocholines and the diameter of nanotubules formed from lipid mixtures containing diacetylenic phosphocholine and a short-chain "spacer" lipid. Microscopic structures in the aqueous dispersions of equimolar mixtures of diacetylenic phospholipid, DCm,nPCS, and saturated spacer lipids (DCm'PCs) were studied to understand and formulate the basis for developing the "design" rules for the formation of stable nanoscale structures. An increase in the number of n resulted in an increase in the diameter of the tubules produced by the mixtures. Circular dichroism (CD) spectra of these mixtures were analyzed and the very complex CD spectra clearly confirmed the chiral nature of the nanotubule architecture. Tubules from most of the mixtures demonstrated long-term storage stability.