Laser-induced flexible Cu@NC/graphene electrode integrated with smartphone for on-site and non-enzymatic glucose monitoring

Abstract

Background: Accurate, rapid and on-site quantification of glucose (Glu) is crucial for the management of diabetes and its complications as well as food safety monitoring. Electrochemical sensors for non-enzymatic Glu quantification have attracted significant attention due to their ease of miniaturization, straightforward integration, high sensitivity and fast response. However, conventional non-enzymatic sensors still largely rely on large laboratory instruments and rigid electrodes, making it difficult to fully meet the requirements for on-site real-time detection. Results: In this work, we report the detailed design of a portable non-enzymatic sensor combined with a Bluetooth-enabled smartphone and a flexible electrode for on-site detection of Glu. The flexible electrode was based on a three-dimensional porous laser-induced graphene (LIG) supported with nitrogen-doped carbon encapsulated copper nanoparticles (Cu@NC/LIG), which was prepared through laser irradiation on a Cu-BTC/ LIG surface. This rational design combines the three-dimensional conductive network and inherent flexibility of LIG with the high electrocatalytic activity of Cu@NC for Glu oxidation. Results show that the constructed sensor exhibits a wide linear range for Glu detection (1 & micro;M to 8 mM), a low detection limit (0.53 & micro;M), and satisfactory repeatability, stability, flexibility, response speed, and anti-interference capability. Furthermore, the sensor was integrated with a smartphone and successfully applied to detect Glu in complex food and beverages, achieving a satisfactory recovery rate. Significance and novelty: This work demonstrates the practical potential of this convenient laser-fabricated, flexible sensor for portable and intelligent on-site detection platforms. The described laser scribing procedure permits the rapid, low-expense generation of high-caliber electrochemical sensors, made more effective through the strategic embedding of customized MOF-originating composites.