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 elect ropolymerization on Au-surfaces (Au-electrodes, Au-quartz crystals or Au-gl ass slides). The electrolysis time controls the film thickness on the elect rodes. Addition of glucose to the copolymer film leads to the ligation of t he sugar to the boronic acid sites and results in the swelling of the polym er. Faradaic impedance spectroscopy, chronopotentiometry, surface plasmon r esonance spectroscopy (SPR), and microgravimetric quartz-crystal-microbalan ce measurements (QCM) are employed to characterize the swelling of the poly mer 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 swel ling degree of the polymer film at variable glucose concentrations, the pol ymer matrix is used as an active medium for the sensing of glucose.