Characterization of glucose responsive phenylboronic acid-based hydrogel using optical coherence tomography

In this work, we investigate the use of optical coherence tomography (OCT) in characterizing a glucose responsive hydrogel based sensor that employs a synthetic receptor system, phenylboronic acids (PBA) as oppose to naturally occurring receptors, such as glucose oxidase. OCT based material deflection technique, based on Hertz contact theory, measures the degree of deflection in a material in response to the expansion and contraction of the hydrogel to calculate glucose concentrations. The glucose responsive hydrogel sensor was fabricated using soft lithography of a polydimethylsilozane (PDMS) flexible reservoir with a 10 nm thick layer of gold on the interior surface of the reservoir. The reservoir was fabricated to contain the hydrogel synthesized from acrylamide hydrogel that was co-polymerized with 3-acrylamideophenylboronic acid. The glucose responsiveness of the hydrogel within the sensor system is measured by analyzing the change in axial depth of the flexible PDMS and were found to correlate linearly with the volumetric changes in response to glucose.