Post-Assembly of Oxidation-Responsive Amphiphilic Triblock Polymer Containing a Single Diselenide

Linear amphiphilic triblock polymers containing a single diselenide (SeSe-tri-ABP) are synthesized by coupling reactions. They self-assemble into spherical micelles 1 in aqueous solution. A remarkable morphology transformation of the micelles is confirmed through dynamic light scattering (DLS) and transmission electron microscopy (TEM). The release behavior of a model molecule, Rhodamine B (RB), is studied by UV-vis spectrophotometry. It is found that post-assembly from micelles 1 to micelles 2 is induced by the oxidation-responsive cleavage of the diselenide group in the oxidation solution. Interestingly, the RB release studies reveal that these micelles release RB in a diphasic pattern (slow after initial fast release) within 24 h under an oxidative environment. In contrast, minimal drug release (<20%) is observed within 24 h for SeSe-tri-ABP micelles under aqueous conditions. Meanwhile, this release behavior of the RB-loaded micelles can be tuned by the post-assembly of oxidation-responsive SeSe-tri-ABP in different oxidation conditions, providing a promising platform for controlled delivery of nanocarriers.