Glucose Response Kinetics and Permeability of a Composite Hydrogel Membrane

A series of composite hydrogel films containing 3-aminophenylboronic acid (AAPBA) with different thicknesses based on chitosan (CS) interpenetrating microgels were prepared on glass sheets. The gel film's response to glucose was measured by ultraviolet spectrophotometry. The results showed that the gel with 10 mol% AAPBA showed the strongest optical response. Alizarin red S (ARS) and methyl orange (MO) were both adsorbed and desorbed from the gel film. The pore diffusion coefficient of the non-interacting solute, methyl orange, showed that the hydrogel had good permeability to water-soluble organic molecules. The apparent diffusion coefficient (8.05 x 10(-8) cm(2)/s) of the thin gel (0.157 mm) was lower due to the influence of the kinetics of the gluconophile bond of 3-aminobenzoborate semisulfate (PBA) or due to a structural rearrangement. The diffusion coefficient of the thicker gel (0.430 mm) was 1.1 x 10(-7) cm(2)/s, and glucose diffusion was the rate-limiting process. The specific amount of ARS bound in the gel was 27 mu mol/mL, which was consistent with the amount of PBA fixed in the gel (25 mu mol/mL). MO underwent nonspecific binding in the gel. The photoresponse of the gel toward glucose was reversible under physiological pH. The linear response and stability of the gels toward glucose suggest they may be used in various glucose-sensing technologies.