Preparation and characterization of novel functional tri-block copolymer for constructing temperature/redox dual-stimuli responsive micelles

Herein, we reported a novel tri-block copolymer synthesized by segmented ring-opening polymerization of temperature-sensitive 5-(pyrrolidine-1-carbonyl) oxepan-2-one monomer (VPyCL) and redox-sensitive macrocyclic disulfide-substituted carbonate monomer (MSS). The structure of the copolymers was confirmed by GPC, 1H NMR and 13C NMR. The obtained tri-block copolymers could self-assemble in aqueous solution to form well-structured micelles, with the mPEG-b-PVPyCL block acting as the hydrophilic coronal and the PSS block acting as the hydrophobic core. Dynamic light scattering (DLS) studies confirmed that micelles formed by these tri-block copolymers with different block ratios could respond to different temperature ranges during the heating/cooling process and respond to reducing agent glutathione (GSH). In addition, transmission electron microscopy (TEM) results further confirmed the polymeric micelles’ dual-stimuli responsiveness. The potential application of this type of dual-stimuli responsive micelles in drug delivery systems was evaluated using doxorubicin (DOX) as the model molecule. The stimulus-dependent responsive behaviors of obtained micelles can be applied to the construction of smart materials capable of performing multiple functions under the appropriate conditions.