Chitosan cryogel with embedded gold nanoparticles decorated multiwalled carbon nanotubes modified electrode for highly sensitive flow based non-enzymatic glucose sensor

This work describes the combined electrocatalytic and synergistic properties of gold nanoparticles (AuNPs) decorated multiwalled carbon nanotubes (MWCNTs) and the large surface area of chitosan (CS) cryogel for the fabrication of a highly sensitive and stable electrochemical non-enzymatic sensor. MWCNTs were pre-mixed with citrate ions that serve as the substrate for gold deposition along their chains. The AuNPs-MWCNTs nanocomposite and chitosan cryogel were easily modified on a gold electrode in only 1 h by freezing and thawing of the mixture after casting it on the electrode surface. Glucose, as a model analyte, was measured by the developed electrode in a flow-injection amperometric system. A fast response time and excellent sensitivity were obtained. The sensor exhibited a linear range between 0.001 and 1.0 mM with a low detection limit (0.5 μM) and a high operational stability (525 injections). There were no effects from the common interferences found in physiological levels in blood samples. After measuring glucose in human blood plasma using this sensor, the results were in good agreement (P > 0.05) with those obtained from the standard spectrophotometrically-measured hexokinase method employed clinically. These good performances made this sensor a potential alternative tool for the detection of glucose and other oxidizable analytes.