Rapidly thiol-responsive degradable block copolymer nanocarriers with facile bioconjugation

Degradation of amphiphilic block copolymer (ABP) micelles in response to external stimuli (stimuli-responsive degradation) is a desired property in the design of controlled delivery vehicles. Here, a versatile methodology that combines facile carbodiimide coupling polycondensation with controlled radical polymerization to synthesize thiol-responsive degradable ABP micelles is described. These smart micelles consist of a hydrophobic degradable polyester block with disulfide linkages labeled repeatedly along the main chain; more importantly, in response to thiols they exhibit rapid and controlled degradation, thereby leading to enhanced release of encapsulated model drugs. Moreover, the proposed method allows for a facile bioconjugation of hydrophilic coronas using cell-targeting biomolecules during polymerization.