title: Synthesis and reduction-responsive disassembly of PLA-based mono-cleavable micelles.
abstract: Stimuli-responsive block copolymers and their self-assembled nanostructures have been extensively studied as effective building blocks in construction of various nanomaterials in nanoscience and nanotechnology. A promising stimuli-responsive platform involves an incorportion of reduction-responsive disulfide linkages that can be cleaved to corresponding thiols when needed. Herein, we describe a novel approach utilizing a combination of ring-opening polymerization and a facile coupling reaction to synthesize a reduction-responsive triblock copolymer comprising biocompatible polylactide (PLA) and poly(ethylene glycol) (PEG) blocks, thus PEG-b(PLA-ss-PLA)-b-PEG (ssBCP). This copolymer self-assembles to form colloidally-stable mono-cleavable micelles having single disulfides in hydrophobic PLA cores surrounded with PEG coronas in aqueous solution. The reductive cleavage of the core disulfides results in changes in micelle morphologies to smaller nanostructures or larger aggregates, depending on the nature of reducing agents. In the presence of glutathione (a cellular reducing agent), the micelle size increases, which enhances the release of encapsulated anticancer drugs in vitro. For biological perspectives, the ssBCP micelles having hydrophilic PEG corona are non-cytotoxic and exhibit enhanced colloidal stability as well as non-specific interactions with proteins.
authors.affiliation: Department of Chemistry and Biochemistry, Concordia University, Montreal, Quebec, Canada H4B 1R6.
authors.forename: Alexander
authors.initials: A
authors.lastname: Cunningham
authors.affiliation: Department of Chemistry and Biochemistry, Concordia University, Montreal, Quebec, Canada H4B 1R6.
authors.forename: Na Re
authors.initials: NR
authors.lastname: Ko
authors.affiliation: Department of Chemistry and Biochemistry, Concordia University, Montreal, Quebec, Canada H4B 1R6. Electronic address: john.oh@concordia.ca.
authors.forename: Jung Kwon
authors.initials: JK
authors.lastname: Oh
mesh_terms: D002850:Chromatography, Gel; D019344:Lactic Acid / Q000737:chemistry*; D008823:Micelles; D046529:Microscopy, Electron, Transmission; D010084:Oxidation-Reduction; D011091:Polyesters; D011108:Polymers / Q000737:chemistry*; D066244:Proton Magnetic Resonance Spectroscopy
chemical_list: D008823:Micelles; D011091:Polyesters; D011108:Polymers; D019344:Lactic Acid; C033616:poly(lactide)
keywords: Amphiphilic block copolymers; Diassembly; Drug delivery; Micelles; Polylactide; Stimuli-responsive degradation