The crystallization of molecules with polar and hydrophobic groups, such as ionic amphiphiles and proteins, is of paramount importance in biology and biotechnology. Research published in the Proceedings of the National Academy of Sciences by a Northwestern University collaboration demonstrated how to combine X-ray scattering and theoretical to study how crystalline order within membranes formed by coassembled cationic and anionic amphiphiles can be controlled by varying pH and molecular tail length. Their work suggests how to design bilayer membranes with speciﬁc crystalline arrangements at ambient temperature and physiologically relevant pH environments by suitable choices of molecular headgroups and tails. Changes in crystallinity are likely to affect molecular diffusion rates across membranes and may enable control over the encapsulation and release of molecules within the membrane. Moreover, pH-induced crystalline transformations are likely used by organisms to control metabolic ﬂow in harsh environments.
“Crystalline polymorphism induced by charge regulation in ionic membranes”, Cheuk-Yui Leung, Liam C. Palmer, Sumit Kewalramani, Bao Fu Qiao, Samuel I. Stupp, Monica Olvera de la Cruz, and Michael J. Bedzyk, Proceedings of the National Academy of Sciences, (2013).
Read more here.