Mercapto-responsive polymeric nano-carrier capable of releasing sulfur dioxide

Abstract

Stimuli-responsive polymeric nano-capsules toward a specific biological signaling molecule show great potential in the fabrication of smart and efficient controlled drug vehicles. Herein, we have designed and synthesized an amphiphilic diblock copolymer of PEG₄₅-b-PDNPSEMA₁₆ (PEG = poly(ethylene glycol) and PDNPSEMA = poly(2-(((2,4-dinitrophenyl)sulfonyl)oxy)ethyl methacrylate); the subscripts represent the mean number of repeat units of each block) with 2,4-dinitrophenylsulfonyl ester. PEG₄₅-b-PDNPSEMA₁₆ amphiphilic diblock copolymer could self-assemble to form spherical micelles in aqueous media. The core of formed micelles contains hydrophobic PDNPSEMA domains, which can load hydrophobic species within the core. The 2,4-dinitrophenylsulfonyl ester moiety can be selectively cleaved upon incubation with mercapto-containing species to give SO₂, which can serve as a SO₂ carrier. Thus, mercapto-containing species exhibit the ability to alter the amphiphilicity and further the self-assembly behavior of PEG₄₅-b-PDNPSEMA₁₆. The release of payloads in the core of micelles can be accelerated specifically by triggering the mercapto-containing species. We envisage that this polymer model could broaden the scope of biological molecule responsive macromolecular systems and provide a new platform to fabricate mercapto-responsive biomedicine materials.