Closed- and open-end tubules composed of cyclic lipids: Effect of chain length on morphological change

In this paper we describe the microscopic observation of tubules made from cyclic lipids with different alkyl chain lengths (20, 24, and 28 carbon atoms) by using phase-contrast microscopy, transmission electron microscopy, and scanning electron microscopy. Cooling after incubation produced the rod-like lipid self-assemblies. These microscopic observations revealed that there are two types of tubules: closed-end tubules observed in the dispersion of the cyclic lipids containing alkyl chains 20 and 24 carbons long, and open-end tubules observed in the dispersion of the cyclic lipid with alkyl chains 28 carbons long.