Electrostatic interactions are essential in the structure and function of biological entities since most biomolecules are charged. As a result of these charges, oppositely charged biomolecules co-assemble into functional units where ionic concentrations play a key role. Most co-assembled biomolecular units have some inherent asymmetry that renders them functionality. An important component of understanding function of assemblies is through the study of their symmetry or conversely the symmetries that they "break". Symmetric electrostatic interactions alone have shown to spontaneously break symmetries, such as the formation of helical (chiral, which means broken mirror image) ionic nano-patterns on fibers. They also break icosahedral symmetry and lead to faceting of vesicles or spherical shells of co-assembled charged molecules of opposite charge into icosahedra without rotational symmetry. Another type of symmetry breaking that drives self-assembly at larger length scales into networks (gels) is associated with the interfaces created by co-assembled charged molecules. These composition ionic heterogeneities create interfaces that storage charge and provide a mechanism of long-range interactions. In this talk we discuss the physics behind the formation of ionic nano-patterns in fibers, membranes and gels of co-assembled macroions of oppositely charged molecules. We describe the symmetries these ionic heterogeneities break and give examples of their associated functions.
