Formation of chiral nanotubes by the novel anthraquinone containing-achiral molecule

Self-assembled lipid nanotubes arouse lots of interest due to their exceptional properties such as very simple production procedures, large variety of applications and high biocompatibility. In this study, the new eccentric but simple molecule, AQua (AQ-NH-(CH2)(10)COOH; where AQ is anthraquinone), which integrates redox-active and pH sensitive character with nanotube forming capability has been designed. AQua forms self-assembled nanotubes by the chiral symmetry-breaking mechanism, in a high yield in the presence of ethanolamine. The nanotubes obtained in AQua-ethanolamine mixture are stable with time and resistant against drying and dilution at constant pH. However, pH change with dilution (without pH control) causes the unfolding of the nanotubes indicating the pH sensitive character. Existence of redox active anthraquinone group along with the carboxylic acid moiety gives the probability of reversibly controllable character to our nanotubes. The effect of the base type which is used to adjust the pH of the dispersion has also been investigated, and helix-tube-ribbon mixture is obtained when NaOH is used instead of ethanolamine. Although there are limited number of studies particularly in the field of reversibly controllable and/or redox active lipid nanotubes, controlled self-assembly and disassembly of these appreciable aggregates are very important for their usage in special applications. Thus, this study is hoped to be one of the remarkable studies for the development of reversibly controllable, redox active self assembled nanotubes. (C) 2012 Elsevier Inc. All rights reserved.