Laser-Treated Screen-Printed Carbon Electrodes for\nElectrochemiluminescence imaging

Electrochemiluminescence (ECL) is\nnowadays a powerful technique\nwidely used in biosensing and imaging, offering high sensitivity and\nspecificity for detecting and mapping biomolecules. Screen-printed\nelectrodes (SPEs) offer a versatile and cost-effective platform for\nECL applications due to their ease of fabrication, disposability,\nand suitability for large-scale production. This research introduces\na novel method for improving the ECL characteristics of screen-printed\ncarbon electrodes (SPCEs) through the application of CO<sub>2</sub> laser treatment following fabrication. Using advanced ECL microscopy,\nwe analyze three distinct carbon paste-based electrodes and show that\nlow-energy laser exposure (ranging from 7 to 12 mJ·cm<sup>–2</sup>) enhances the electrochemical performance of the electrodes. This\nenhancement results from the selective removal of surface binders\nand contaminants achieved by the laser treatment. We employed ECL\nmicroscopy to characterize the ECL emission using a bead-based system\nincorporating magnetic microbeads, like those used in commercial platforms.\nThis approach enabled high-resolution spatial mapping of the electrode\nsurface, offering valuable insights into its electrochemical performance.\nThrough quantitative assessment using a photomultiplier tube (PMT),\nit was observed that GST electrodes could detect biomarkers with high\nsensitivity, achieving an approximate detection limit (LOD) of 11\nantibodies per μm<sup>2</sup>. These findings emphasize the\npotential of laser-modified GST electrodes in enabling highly sensitive\nelectrochemiluminescent immunoassays and various biosensing applications.