Open AccessPolymerization Induced Self-Assembly of Alginate Based Amphiphilic Graft Copolymers Synthesized by Single Electron Transfer Living Radical Polymerization
Author(s) -
Vitaliy Kapishon,
Ralph A. Whitney,
Pascale Champagne,
Michael F. Cunningham,
Ronald J. Neufeld
Publication year - 2015
Publication title -
biomacromolecules
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.689
H-Index - 220
eISSN - 1526-4602
pISSN - 1525-7797
DOI - 10.1021/acs.biomac.5b00470
Subject(s) - copolymer , amphiphile , polymerization , polymer chemistry , chain transfer , radical polymerization , living free radical polymerization , chemistry , living polymerization , self assembly , reversible addition−fragmentation chain transfer polymerization , electron transfer , materials science , chemical engineering , photochemistry , polymer , organic chemistry , engineering
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.