Portable Electrochemiluminescence Platform With Laser-Induced Graphene-Based U-Shaped Bipolar Electrode for Selective Sensing of Various Analytes

Abstract

In recent years, rising need of microfluidics-based point-of-care devices has led to cost-effective solutions at or near the location of patients. With this motivation, herein, laser-induced graphene (LIG)-based electrochemiluminescence (ECL) system loaded with U-shaped bipolar electrode (U-BPE) has been developed and its application for enzymeless sensing of various biomarkers has been validated. Low-cost and easily available flexible polyimide (PI) sheet has been effectively used for the fabrication of LIG U-BPE ECL device. With optimized speed and power, the ablation of CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> laser on PI has been carried out to create graphenized driving electrodes and U-BPE in a single step. A cost-effective and portable 3-D printed platform has been developed for image sensing of ECL signals. The bulky power supply was effectively replaced by a dual-functional android smartphone to provide power to the LIG U-BPE ECL sensor and to capture the ECL signals. With this mini-platform, determination of various analytes, such as H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> , D-glucose, lactate, and choline, has been accomplished in a linear range of 0.1-50, 0.1-70, 1-100, and 1- 100 μM with limit of detection (LOD) of 4.36, 2.51, 5.32, and 4.01 μM, respectively. An interference study has been performed and it was found that after adding interfering compounds in analytes, ECL signal intensity was reduced to less than 5%. Hence, it was proven that LIG U-BPE ECL device was very selective to different analytes concerning to their voltages.