Self-Assembly of Supramolecular Structures: The Role of Fluctuations

This is a short review of experiments performed at our Laboratory on the self-assembly of supramolecular structures in vitro. The experiments show that fluctuations of a relevant parameter driven from outside, as well as spontaneous fluctuations of local concentration occurring under or near thermodynamic instability, and non-linear interactions between these two types of fluctuations, can trigger or enhance the self-assembly of supramolecular order. The pattern generated by spontaneous fluctuations is capable of setting the canvas for the resulting self-assembled structure. Experiments performed so far concern two diverse systems: a polysaccharide widely found in nature, which makes firm aqueous biostructural gels (agarose), and a synthetic model system of bioelastomers, the polypentapeptide (Val-Pro- Gly-Val-Gly)n which represents the most significant sequence of the bioelastomeric protein, elastin. Work on the latter system was and is being done in collaboration with D.W. Urry’s group of Birmingham, AL.