Synthesis of PEO-based glucose-sensitive block copolymers and their application for preparation of superparamagnetic iron oxide nanoparticles

Amphiphilic block copolymers were synthesized by reversible addition fragmentation chain transfer (RAFT) radical block polymerization of N-vinylimidazole and 3-(methacrylamido)phenylboronic acid using poly (ethylene oxide) (PEO)-based xanthate type of RAFT agent and 2,2′ -azobisisobutyronitrile (AIBN) in dimethylformaide (DMF) at 90∼110 °C for 24 h. Poly(ethylene oxide-b-3-(methacrylamido)phenylboronic acid) and poly(ethylene oxide-b-N-vinylimidazole-b-3-(methacrylamido)phenylboronic acid) were prepared successfully through the sequential monomer addition method. Both block copolymers were found to exhibit glucose-responsive behavior via the feasibility test for complex formation with Alizarin Red S (ARS). The ratio of molecular weight of the poly(N-vinyimidazole) to the poly(3-(methacrylamido) phenylboronic acid) appeared to play an important role in the pH- & glucose- responsive behavior. The resulting block copolymers were used successfully as polymeric stabilizers to prepare water-soluble Fe₃O₄ nanoparticles. All the materials were characterized by the combination of ₁H nuclear magnetic resonance (NMR), size exclusion chromatography (SEC), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and x-ray diffraction (XRD) analyses. Keywords: pH- and glucose-responsive block copolymer, RAFT polymerization, ring-opening polymerization, xanthate- type agent, ARS complex, water-soluble iron oxide nanoparticles.