Highly stretchable, adhesive and conductive hydrogel for flexible and stable bioelectrocatalytic sensing layer of enzyme-based amperometric glucose biosensor

Highly stretchable, adhesive and conductive triblock hydrogel was synthesized and utilized as a flexible and stable bioelectrocatalytic sensing layer of enzyme-based amperometric glucose biosensor. The hydrogel was prepared through one-pot polymerization of 2-acrylamido-2-methyl-1-propanesulfonic acid, methacrylamide, and hydroxyethyl methacrylate. The physical and chemical properties of the hydrogel were characterized with X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and electrochemical techniques. Glucose oxidase (GOx) and chitosan (CTS) embedded hydrogel was drop-coated on glassy carbon electrode (GCE) and screen printed graphite electrode (SPGE). The resulting GOx/CTS/hydrogel-GCE and GOx/CTS/hydrogel-SPGE exhibited excellent mediated bioelectrocatalytic oxidation current for glucose. The calibration curve of glucose by the GOx/CTS/hydrogel-GCE showed the linear range from 0.25 to 15 mM with the sensitivity of 27.0 µA mM⁻¹ cm⁻². This GOx/CTS/hydrogel-based sensing layer coated on the SPGE was stable against bending, and the response to glucose was almost same irrespective of the bending angles (0, 30, 60, and 90 degree). In addition, the response to glucose was not interfered by various organic and inorganic interfering species, allowed to detect glucose in goat serum. Furthermore, the GOx/CTS/hydrogel-GCE kept its original activity of 99.64 % during 30 days’ storage under dry state in refrigerator.