Real-time Monitoring of ROS Secreted by Ana-1 Mouse Macrophages by Nanomaterial Sensitized Electrochemiluminescence

Abstract Reactive oxygen species (ROS) are closely related to numerous physiological and pathological processes, but the real-time monitoring of ROS is still a challenge because of their rapid diffusion, low concentration, and short half-life in biological systems. Herein, two excellent electrochemiluminescent (ECL) cytosensors were developed for the real-time detection of ROS. Using poly-L-lysine (PLL) to promote cell adhesion, based on the prefunctionalization with gold nanoparticles (AuNPs) or AuNPs/titania nanotubes (TiO2NTs) nanocomposites for indium-doped tin oxide (ITO)-coated glass, two sensors are acquired. For AuNP-functionalized one (Sensor 1), the result for the H2O2 assay demonstrated a good linear response from 0.01 µM to 0.2 µM and a limit of detection down to 8.9 nM. After capitalizing on the synergetic effect of AuNPs and TiO2NTs, the AuNP/TiO2NT-based biosensor (Sensor 2) displayed better sensitivity toward H2O2 detection with a linear response from 5 nM to 0.1 µM and a lower limit of detection (LOD) of 2 nM. On this basis, we changed the cell density and stimulated cells with different drugs to detect the production of ROS, indicating the good applicability of the biosensors.