CONTROLLING THE MORPHOLOGY OF CHIRAL LIPID TUBULES

Several techniques for controlling the morphology of self-assembled li pid tubules are investigated by using circular dichroism spectroscopy and electron microscopy. These studies show that variations in the mol ecular structure of the diacetylenic phospholipid, lipid concentration , and solution conditions allow for control of the number of bilayers in the tubule walls, but not their diameter. Tubules formed in water a nd mixtures of alcohols adopt interesting morphologies and allow for f urther control of tubule structure. In addition, studies of lipids wit h different acyl chains show that tubule morphology is sensitive to th e degree of order within the chains. Because of the chiral molecular a rchitecture in lipid tubules, intense peaks in their circular dichrois m spectra are observed. These peaks can be monitored to obtain informa tion on the tubule morphology. This information is correlated to direc t observations made using electron microscopy. Results of these studie s have led to the optimization of large scale preparations of tubules for technological applications.