Polymerization of dopamine accompanying its coupling to induce self-assembly of block copolymer and application in drug delivery

Abstract

Polymer self-assembly has attracted intensive technological and scientific consideration due to its intriguing practicability and fascinating versatility. A wide range of morphologies, including micelles, vesicles, cylinders, and many other hierarchical assemblies, have been crafted through polymer self-assembly for many decades. Herein, we report a facile and robust strategy to fabricate polymeric assemblies that possess precisely controllable morphology through copolymer self-assembly. The results show that these copolymers can be self-assembled into two different polymeric assemblies, depending on the choice of polymer structure. In this self-assembly process, the polymerization of dopamine and the coupling between polydopamine and block copolymer are performed in succession (denoted the polymerization-coupling process), which synergistically induces the self-assembly of block copolymer to yield ordered structures, including micelles and vesicles. The key to this strategy is to exploit the self-polymerization of dopamine, which results in polymeric vesicles with cross-linking structures and enhances their stability without additional cross-linking agents. These polymeric vesicles exhibit an ideal drug loading capacity toward doxorubicin (DOX) and bortezomib (BTZ) because of a number of carboxyl groups, conjugated systems, and catechol moieties, while the drug-loaded polymeric vesicles are sensitive to the endogenous weak acidic microenvironment, unloading the drug to fulfil their drug delivery role. Therefore, this strategy provides new insights into the development of molecular self-assembly, and the resultant polymeric assemblies show direct potential applications in the field of drug delivery.