Gold-dispersed hierarchical flower-like copper oxide microelectrodes for the sensitive detection of glucose and lactic acid in human serum and urine

Abstract

Herein, we report self-supported gold-dispersed copper oxide microflowers (Au@CuO MFs) on copper microelectrodes (CMEs) as a sensitive platform for the sensing of glucose and lactic acid in human serum and urine samples. The direct growth of a new class of gold-dispersed copper oxide microflowers on Cu microelectrodes involves growing flower-like passivated copper microelectrodes in nitric acid followed by the galvanic replacement of copper atoms with gold atoms without employing any surfactant or polymer or without the use of any catalysts or complicated procedures. The as-fabricated gold-dispersed copper oxide microflower microelectrodes (Au@CuO MFs|CME) were employed as potential signal transducers for the sensitive detection of glucose and lactic acid in practical samples. The present Au@CuO MFs|CME microsensor demonstrates an extensive linear detection range from 5.0 μM to 0.5 mM for glucose with a low limit of detection (LOD) of ∼1.41 μM and a sensitivity of ∼4.14 mA μM⁻¹ cm⁻², and from 100 nM to 88.0 μM for lactic acid with a LOD of ∼27.0 nM and a sensitivity of ∼6.19 mA μM⁻¹ cm⁻². The present multi-functional nanoarchitectured Au@CuO MFs|CME microsensor is anticipated to offer unique surface characteristics and synergistic effects, and can be exploited in various electrochemical fields.