Polyvinyl alcohol as a crucial omissible polymer to fabricate an impedimetric glucose biosensor based on hierarchical 3D-NPZnO/chitosan.

Highly stable and reliable monitoring of glucose is of great importance for diabetes patients. This paper describes the application of two types of polymer for developing a reliable impedimetric glucose biosensor by designing an efficient nanoporous microenvironment for enzyme loading. Polyvinyl alcohol (PVA) was used as a sacrifice polymer to prepare a uniform 3D-nanoporous ZnO (3D-NPZnO) platform through electrodeposition of ZnO/PVA layer followed by PVA elimination via annealing. The carbohydrate polymer, chitosan (CTS), with a high isoelectric point (pI = 7.0-9.0), was selected in accompanying with 3D-NPZnO (pI = 9.5) to provide a hierarchical 3D-NPZnO/CTS microenvironment of a favorable isoelectric point for glucose oxidase enzyme (pI = 4.2) loading. The characterization of structural features and monitoring of the biosensor fabrication process was performed using FE-SEM, EDX, TGA-DTG, FTIR, UV-Vis, BET-BJH, XRD, CV, and EIS techniques. The fabricated platform, which shows a wide linear range of 1.0-18.0 mM and a low detection limit of 0.2 mM for glucose determination, was successfully used for real sample analysis. The proposed fabrication method can be applied for immobilizing the other low isoelectric point enzymes and biomolecules.