Lab on Pipette: Robust Biochemical Sensing with Functional Laser-Induced Graphene Electrode Array for On-Site and Disposable Urine Analysis

Urine, abundant in disease-related biomarkers, offers advantages such as easy collection and noninvasiveness. Portable biochemical sensors are ideal for efficient on-site applications due to their flexibility and accessibility. However, existing sensors face challenges in complex sample operations and limited sensor renewal, hindering large-scale and convenient urine analysis. This study presents the "lab on pipette" (LOP) concept to address these issues, enabling efficient on-site urine analysis. The LOP system integrates a multifunctional pipette tip and a miniaturized system, facilitating the detection of multiple biomarkers in urine. Laser-induced graphene (LIG) technology fabricates an electrochemical electrode array on flexible polyimide, and custom-designed electrical interfaces ensure quick plug-and-play connections. Gold nano dendrites, Prussian blue (PB), and nickel hexacyanoferrate (NiHCF) form a multilayer functional interface, enabling highly sensitive detection of pH, hydrogen peroxide, glucose, and ascorbic acid with pH compensation. NiHCF doping enhances PB stability, while nanoalumina-doped porous enzyme membranes improve sensor repeatability and reliability. Gold nano dendrites anchor the enzyme membrane on curved surfaces, ensuring robust performance. The LOP achieves detection limits of 7.19 and 8.57 μM for glucose and ascorbic acid, respectively. Its low cost, disposability, portability, and reliability highlight its potential for on-site biochemical detection and personalized health monitoring.