Regulating molecular assembly with chemical fuels— Spinning ribbons, dissipative structures, and an approach towards synthetic life

Abstract

Molecular self-assembly is the process in which molecules combine into superstructures held together through non-covalent interactions. Over the last decades, supramolecular chemists have perfected this art, and we can now create Gigadalton structures in which each atom is placed with angstrom precision. More importantly, the unique properties of the emerging assemblies have found their way into everyday life, like, for example, the liquid crystals in our displays. Nevertheless, biology entirely overshadows us regarding assembly with molecular building blocks. Indeed, the biological cell has the same molecular toolbox for creating structures; it also uses non-covalent interactions to hold molecules together. Biology uses another trick. Biological structures are governed not only by non-covalent interactions but also by reactions forming covalent ones. Arguably, molecular self-assembly offers the structures; chemical reactions govern the dynamics and functions of these structures. Biological structures are sustained and regulated in the non-equilibrium regime through chemical reaction cycles that convert energy. The implications, rules, and mechanisms there are poorly understood.

In this lecture, I will discuss my team’s effort to elucidate the rules of non-equilibrium self-assembly regulated by chemical reaction cycles. Next, I will describe a simple yet versatile chemical reaction cycle that can be coupled to self-assembly to create chemically fueled assemblies. Finally, I will highlight three recent examples of chemically fueled, non-equilibrium assemblies with vastly different properties than their in-equilibrium counterparts—ribbons that spin spontaneously as they consume fuel and dissipative droplets that periodically form and dissolve when fueled continuously. I will close the lecture with our vision towards synthetic life.