Miniaturized Electrochemiluminescence Platform With Laser-Induced Graphene-Based Single Electrode for Interference-Free Sensing of Dopamine, Xanthine, and Glucose

Electrochemiluminescence (ECL) plays a vital role in the development of point-of-care testing (POCT) devices. Conventional electrochemical and bipolar electrochemical-based ECL systems are time-consuming, expensive, and required more fabrication steps. To eliminate such challenges, in this work, for the first time, novel laser-induced graphene (LIG)-based single electrode (SE) system has been developed, and its application in enzymeless ECL detection of multiple analytes has been validated. SEs were fabricated over polyimide (PI) substrate by directing CO₂ laser leading to the creation of graphene over PI in a single step by optimizing the speed and power of the laser. Android smartphone was effectively used to provide dual functioning such as capturing the ECL image and driving the LIG-SE-ECL sensor. With optimized parameters, determination of hydrogen peroxide (H₂O₂), D-glucose (G), xanthine (X), and dopamine (D) was carried in the linear range from 0.1 to <inline-formula> <tex-math notation="LaTeX">$70~\mu \text{M}$ </tex-math></inline-formula>, 0.1 to <inline-formula> <tex-math notation="LaTeX">$70~\mu \text{M}$ </tex-math></inline-formula>, 0.1 to <inline-formula> <tex-math notation="LaTeX">$100~\mu \text{M}$ </tex-math></inline-formula>, and 0.1 to <inline-formula> <tex-math notation="LaTeX">$100~\mu \text{M}$ </tex-math></inline-formula>, with a limit of detection (LOD) 1.71, 3.76, 1.25, and <inline-formula> <tex-math notation="LaTeX">$3.40~\mu \text{M}$ </tex-math></inline-formula>, respectively. An interference study was performed and it was observed that LIG-SE-ECL device showed effective selectivity for different analytes with their respective voltages. The developed miniaturised, low-cost ECL platform can be suitably used in many diverse applications such as POCT, environmental monitoring, and multiple biomedical applications.