Sputtered Iridium Oxide Electrodes Optimization and Implementation for Impedimetric Identification of <i>S</i>. <i>aureus</i> and <i>P</i>. <i>aeruginosa</i> Biofilms

Electrochemical impedance spectroscopy (EIS) has been established as an effective technique for bacterial biofilm detection. Through the need for miniaturization, the application of novel electrode materials gains interest. In this study, we introduce Sputtered IRidium Oxide Film (SIROF) electrodes of varying sizes and geometries as sensors for biofilm detection. Pre-emptive cyclic voltammetry (pre-cycling) was used to transform as-sputtered anhydrous iridium oxide films into hydroxides, reducing the impedance and allowing the material to be adopted for miniaturized biofilm sensors. Our investigation showed that especially lower scan rates during this pre-cycling process reduced the interfacial impedance, hence optimizing electrode performance for this application. Using EIS in combination with pre-cycled SIROF electrodes, we detected biofilm growth within 24 hours and successfully distinguished between biofilms of S. aureus and P. aeruginosa . Additionally, we analyzed the influence of electrode size on biofilm detection and characterization. This study highlights SIROF electrodes as a promising platform for sensitive and scalable biofilm monitoring.