Glucose-responsive poly(vinyl alcohol)/β-cyclodextrin hydrogel with glucose oxidase immobilization

Glucose-responsive poly(vinyl alcohol)/β-cyclodextrin (PVA/β-CD) hydrogels cross-linked by citric acid were prepared through an environment-friendly synthesis procedure. The glucose oxidase (GOx) was physically immobilized within the β-CD cavity for accurate detection of interstitial fluid glucose levels reaching approximately 1 mM. We evaluated the viscoelastic behavior of the PVA/β-CD solutions through dynamic oscillatory shear testing, and the PVA/β-CD/GOx hydrogel 10 shows the optimal properties with excellent water absorption (312 ± 17%), low solubility, and long moisture retention time (approximately 4.5 h for complete drying at 37 °C). The PVA/β-CD/GOx hydrogel showed the high flexural and tensile strengths of ≥ 400 and ≥ 5 MPa, respectively. Furthermore, the fabricated PVA/β-CD/GOx hydrogel 10 displayed a linear amperometric response (R2 is 0.984) in the glucose concentration range from 1.0 to 5.0 mM with a relatively high sensitivity of 7.58 µA mM−1 and a low detection limit of 5.141 × 10−4 M at low applied potential (0.27 V vs. Ag/AgCl coated with Prussian blue), indicating its great potential as a patch sensor for noninvasive glucose monitoring.