Multifunctional potentiostat for static and fluidic electrochemical sensing: Validation and application to detection of Pseudomonas aeruginosa

This work reports the development and analytical validation of FACILE 2.0, a portable multifunctional potentiostat designed for electrochemical measurements under both static and microfluidic configurations. The platform integrates a compact electrochemical interface, embedded single-board computer, touchscreen control, and programmable flow handling, enabling autonomous execution of cyclic voltammetry, square wave voltammetry, chronoamperometry, and electrochemical impedance spectroscopy. Analytical performance was first validated using benchmark reversible redox systems and electroactive species exhibiting different electron-transfer kinetics. Under static conditions, calibration studies demonstrated high linearity (R2 up to 0.999), repeatability of 8% (RSD), and a limit of detection of 0.7 μM for representative redox probes, values comparable to commercial benchtop and portable potentiostats. Correlation analyses confirmed strong agreement in current response and extracted electrochemical parameters across different techniques. Measurements performed in fluidic mode further demonstrate stable and reproducible responses under controlled flow conditions. Following electrochemical validation, FACILE 2.0, was applied as a representative case study to a label-free immunosensor for the detection of Pseudomonas aeruginosa in untreated tap water. Using square wave voltammetry, the system achieved a limit of detection of 1000 CFU/mL (RSD <10%, n = 5), with high specificity against non-target microorganisms (<10% interference). With a compact footprint (W32 x D18 x H5 cm), low power consumption (<15W maximum), and complete portability (1.93 kg), FACILE 2.0 provides a robust, scalable and field-deployable solution for a broad range of electrochemical applications, including environmental monitoring, industrial quality control, materials research, teaching laboratories, and decentralized biosensing applications.