Lightning the Interface: the Electrochemical Features of Biomolecular Condensates

Phase transition of biomacromolecules can result in a solvent density transition between the dilute and the dense phases. This solvent density transition can lead to a new electrochemical equilibrium between the dilute and the dense phases. Here we discuss the mechanism by which the unique electrochemical environment of condensates can encode different electrochemical features. We introduce how an associative transition of biomacromolecules can result in a segregative transition of ions, forming an electric potential gradient between the dilute and the dense phases, which corresponds to an interfacial electric double layer. We find that this electric double layer serves as an active electric field that can drive spontaneous redox reactions and represents a new functional feature of condensates. This work uncovers that the functions of biomolecular condensates can be determined by their electrochemical environments, expanding our understandings on condensate function beyond the biomolecules driving or participating in phase transition.