title: Polymerization Induced Self-Assembly of Alginate Based Amphiphilic Graft Copolymers Synthesized by Single Electron Transfer Living Radical Polymerization.
abstract: Alginate-based amphiphilic graft copolymers were synthesized by single electron transfer living radical polymerization (SET-LRP), forming stable micelles during polymerization induced self-assembly (PISA). First, alginate macroinitiator was prepared by partial depolymerization of native alginate, solubility modification and attachment of initiator. Depolymerized low molecular weight alginate (∼12 000 g/mol) was modified with tetrabutylammonium, enabling miscibility in anhydrous organic solvents, followed by initiator attachment via esterification yielding a macroinitiator with a degree of substitution of 0.02, or 1-2 initiator groups per alginate chain. Then, methyl methacrylate was polymerized from the alginate macroinitiator in mixtures of water and methanol, forming poly(methyl methacrylate) grafts, prior to self-assembly, of ∼75 000 g/mol and polydispersity of 1.2. PISA of the amphiphilic graft-copolymer resulted in the formation of micelles with diameters of 50-300 nm characterized by light scattering and electron microscopy. As the first reported case of LRP from alginate, this work introduces a synthetic route to a preparation of alginate-based hybrid polymers with a precise macromolecular architecture and desired functionalities. The intended application is the preparation of micelles for drug delivery; however, LRP from alginate can also be applied in the field of biomaterials to the improvement of alginate-based hydrogel systems such as nano- and microhydrogel particles, islet encapsulation materials, hydrogel implants, and topical applications. Such modified alginates can also improve the function and application of native alginates in food and agricultural applications.
authors.affiliation: †Department of Chemical Engineering, ‡Department of Chemistry, and §Department of Civil Engineering, Queen's University, Kingston, Ontario Canada K7L 3N6.
authors.forename: Vitaliy
authors.initials: V
authors.lastname: Kapishon
authors.affiliation: †Department of Chemical Engineering, ‡Department of Chemistry, and §Department of Civil Engineering, Queen's University, Kingston, Ontario Canada K7L 3N6.
authors.forename: Ralph A
authors.initials: RA
authors.lastname: Whitney
authors.affiliation: †Department of Chemical Engineering, ‡Department of Chemistry, and §Department of Civil Engineering, Queen's University, Kingston, Ontario Canada K7L 3N6.
authors.forename: Pascale
authors.initials: P
authors.lastname: Champagne
authors.affiliation: †Department of Chemical Engineering, ‡Department of Chemistry, and §Department of Civil Engineering, Queen's University, Kingston, Ontario Canada K7L 3N6.
authors.forename: Michael F
authors.initials: MF
authors.lastname: Cunningham
authors.affiliation: †Department of Chemical Engineering, ‡Department of Chemistry, and §Department of Civil Engineering, Queen's University, Kingston, Ontario Canada K7L 3N6.
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Neufeld
mesh_terms: D000464:Alginates / Q000737:chemistry*; D001672:Biocompatible Materials / Q000138:chemical synthesis* / Q000737:chemistry; D016503:Drug Delivery Systems; D046911:Macromolecular Substances / Q000138:chemical synthesis / Q000737:chemistry; D008768:Methylmethacrylates / Q000138:chemical synthesis* / Q000737:chemistry; D008823:Micelles; D015394:Molecular Structure
chemical_list: D000464:Alginates; D001672:Biocompatible Materials; D046911:Macromolecular Substances; D008768:Methylmethacrylates; D008823:Micelles