Reversible Light-Responsive Coacervate Microdroplets with Rapid Regulation of Enzymatic Reaction Rate

Graphical Dynamic regulation of coacervate microdroplets as a protocell model has attracted more and more attention in recent years. However, the dynamic regulation of enzymatic reactions has not yet been achieved. A method to regulate enzymatic reactions rate by assembly-disassembly-reassembly of light-induced coacervates is proposed, which could pave the way to the further development of dynamic coacervate-based protocells. Membrane-free coacervate microdroplets are widely utilized as protocell or membrane-less organelle models in the study of cell physicochemical properties. Dynamic regulation of coacervate microdroplets is of great significance because of the close connection between the formation/dissociation of condensate in vivo and physiology and pathology. Here, we describe light-responsive coacervate microdroplets prepared from azobenzene cation trans-azobenzenetrimethylammonium bromide (trans-azoTAB) and anion succinylated amylose (Su-Amy), which are formed by hydrophobic interaction and electrostatic interaction. The rapid and accurate response of azoTAB to light makes the microdroplets disassemble and reassemble within seconds under UV and within minutes under blue light, which provides a method to regulate the enzymatic reaction rates by the light-induced assembly-disassembly-reassembly of the coacervate microdroplets. Our results show a new type of membrane-less protocell model that can realize flexible spatiotemporal control and demonstrate a method for dynamically regulating the rate of enzymatic reactions inside the microdroplets, which provides a feasible scheme for exploring the relationship between physiology and disease in vitro .