A reagentless amperometric glucose biosensor based on 5-amino-1,10-phenanthroline, gold nanoparticles and glucose oxidase

Abstract

Glucose monitoring is essential for the management of diabetes and for ensuring an accurate analysis in clinical and food-related applications. In this study, a reagentless amperometric glucose biosensor was developed based on the layer-by-layer adsorption of 5-amino-1,10-phenanthroline (AP), 13 nm diameter gold nanoparticles (AuNPs), and glucose oxidase (GOx) onto a graphite rod electrode, followed by chemical cross-linking of GOx with glutaraldehyde vapour. AP acted as a redox mediator, enabling an efficient electron transfer, while AuNPs facilitated signal amplification. The biosensor exhibited a wide linear range (0.30–10.0 mM), low limits of detection and quantification (LOD 0.05 mM, LOQ 0.17 mM), a high repeatability (RSD 3.19%) and an acceptable reproducibility (RSD 5.51%), along with an excellent selectivity toward glucose and a satisfactory storage stability (86% signal retention over 7 days), and anti-interference performance against uric and ascorbic acids. These features demonstrate the biosensor’s suitability for routine and point-of-care glucose monitoring. Furthermore, the proposed platform is versatile and can be adapted for the detection of other clinically or environmentally relevant analytes, highlighting its potential for broader analytical applications.