Electrostatic Attraction Between Cationic-Anionic Assemblies with Surface Compositional Heterogeneities

Oppositely charged biomolecules can coassemble into functional units. For example, actin-binding protein complexes have been shown to coassemble into cytoskeleton components,
and cationic-anionic co-assembled peptide amphiphiles have been shown to co-assemble into functional nanofibers. Cationic-anionic co-assemblies have surface charge heterogeneities that result from the delicate balance between electrostatics and packing constraints. Researchers at the NU-MRSEC studying the interaction among assemblies with surface charged heterogeneities have found that attractions among fibers appear as a result of correlations and polarization of surface charged domains. These results reveal the importance of charge heterogeneities in cationic-anionic co-assemblies of complex molecules and suggest a promising strategy for the fabrication of assemblies with predictable surface charge patterns for developing functional biomolecular assemblies.

Surface charge heterogeneities in two different pairs of interacting fibers via charge polarizability. The values of the net short range repulsion among the co-assembled fibers on the pair on the left is lower and leads to weaker fiber-fiber attractions than on the right pair of cylinders.

Y. S. Velichko and M. Olvera de la Cruz "Electrostatic attraction between cationic-anionic assemblies with surface compositional heterogeneities." J. Chem. Phys. 124, 214705-11 (2006). ABSTRACT

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