Characterization of the swelling of acrylamidophenylboronic acid-acrylamide hydrogels upon interaction with glucose by faradaic impedance spectroscopy, chronopotentiometry, quartz-crystal microbalance (QCM), and surface plasmon resonance (SPR) experiments

A m-acrylamidophenylboronic acid-acrylamide copolymer is assembled by electropolymerization on Au-surfaces (Au-electrodes, Au-quartz crystals or Au-glass slides). The electrolysis time controls the film thickness on the electrodes. Addition of glucose to the copolymer film leads to the ligation of the sugar to the boronic acid sites and results in the swelling of the polymer. Faradaic impedance spectroscopy, chronopotentiometry, surface plasmon resonance spectroscopy (SPR), and microgravimetric quartz-crystal-microbalance measurements (QCM) are employed to characterize the swelling of the polymer film upon the binding of glucose. The swelling rate constant, upon the association of glucose to the polymer film, is estimated to be k(sw) = 1.7 x 10(-4) s(-1), while the shrinking rate constant of the polymer film, upon depletion of glucose, is k(sh) = 2.3 x 10(-5) s(-1). By following the swelling degree of the polymer film at variable glucose concentrations, the polymer matrix is used as an active medium for the sensing of glucose.