ATP-Driven Temporal Control over Structure Switching of Polymeric Micelles

An adenosine triphosphate (ATP)-fueled micellar system in the out-of-equilibrium state was constructed based on 4,5-diamino-1,3,5-triazine (DAT)-containing block copolymer. The block copolymer self-assembled into spherical micelles in equilibrium steady state at pH higher than its p K_a. The pendant DAT residues in protonated form acted as ATP catchers via hydrogen bonding and electrostatic interactions. Activated by ATP fuel, the polymeric micelles spontaneously disrupted into small aggregates of ATP/polymer hybrid complexes. The consumption of ATP energy via the enzymatic hydrolysis led to dissociation of the complexes and reversible formation of polymeric micelles. A transient self-assembly cycle, in which the assembly underwent autonomous division-fusion motion, was created using ATP fuel and enzyme; the switching of assembly structure was sustained by continuous supply of ATP fuel. This DAT-containing block copolymer have good biocompatibility, and drug-loaded micelles display ATP-responsive release behavior. It is expected that this ATP-fueled supramolecular assembly system will provide a functional platform for biomimic chemistry and therapeutic applications.