Oxidation responsive mono-cleavable amphiphilic di-block polymer micelles labeled with a single diselenide

A novel diselenide-containing mono-cleavable amphiphilic di-block polymer, denoted MPEG-IPDI-SeSe-IPDI-PPG, composed of one hydrophilic poly(ethylene glycol) monomethyl ether (MPEG) block and one hydrophobic polypropylene glycol (PPG) block, was synthesized via four coupling reactions in sequence. MPEG-IPDI-SeSe-IPDI-PPG is able to self-assemble into spherical micelles in aqueous solution. Subsequently, it was found that the spherical micelles have a oxidation-responsiveness and undergo a morphology transformation from spherical micelles to large compound micelles (LCMs) in an oxidative environment (0.5%wt H2O2) due to the unique oxidation-responsive cleavage of the diselenide group, resulting in an initially fast release of loaded Rhodamine B (RB), followed by slow, continuously increasing release. It is anticipated that these mono-cleavable polymer micelles containing diselenide may find application in the field of drug delivery systems.