Immobilization of Glucose Oxidase on a PVA/PAA Nanofiber Matrix Reduces the Effect of the Hematocrit Levels on a Glucose Biosensor

Abstract

A sensitive and selective amperometric glucose biosensor based on a PVA/PAA nanofiber layer deposited on a copper/Ni electrode was investigated. Typically, many currently available point-of-care glucose sensors demonstrate a decreasing response to the analyte in the presence of increasing hematocrit levels (blood-to-plasma difference). A sensor electrode for glucose is described that displays a reduced sensitivity to changes in hematocrit levels. The base layer of the sensor consists of PVA/PAA-GOD-coated nanofibers impregnated with a mixture of glucose oxidase and a ruthenium redox mediator. It has an average diameter of approximately 510 ± 50 nm (100–150 ± 20 nm for the glucose oxidase aggregates), an average pore diameter of 2.7 ± 0.5 μm and a thickness of less than 20 μm. The copper/Ni electrode has a low electrical resistance, less than 0.01 Ω, and it may be possible to mass produce the biosensor electrode with a uniform electrical resistance. The current of the PVA/PAA-GOD-coated nanofiber glucose biosensor shows no hematocrit effect on glucose measurements at hematocrit levels from 35% to 60% for glucose concentrations from 37.1 mg/dL (2.06 mmol/L) to 544.7 mg/dL (30.24 mmol/L). The glucose sensor with a PVA/PAA-GOD-coated nanofiber deposited on a Copper/Ni electrode on PET film exhibits a relatively short response time (approximately 3 s) and a sensitivity of 0.85 μAmM^­1 with a linear range from 0 to 33 mM glucose. The sensor has excellent reproducibility with a correlation coefficient of 0.9989 and a total nonlinearity error of 2.65%.