B 3Q MAS NMR Study on Glucose-Responsive Micelles Self-assembled from PEG-b-P(AA-co-AAPBA)

Phenylboronic acid (PBA) based glucose-responsive materials have attracted great interests in recent years for developing insulin delivery systems. It is desired to obtain PBA based materials that can response to glucose under physiological pH and understand the mechanism. By using 11B triple-quantum magic-angle spinning nuclear magnetic resonance (11B 3Q MAS NMR) measurements, the glucose-responsive mechanism of micelles self-assembled from poly(ethylene glycol)-b-ploy(acrylic acid-co-acrylamidophenylboronic acid) PEG-b-P(AA-co-AAPBA) is deeply investigated. Different configurations of phenylboronic acid during various steps of glucose-responsive behaviors are clearly analyzed in the 11B 3Q MAS NMR spectra and coordination between carboxyl and PBA is confirmed. By increasing the AA units in PEG-b-P(AA-co-AAPBA), the carboxyl can coordinate with PBA moieties and cause the glucose-responsiveness of micelles even in the weak acid environment.