Surface-Specific Reactivity and Ionic Selectivity in Aluminium Interdigitated Electrode Platforms for Advanced electronic Sensing Interfaces

• All claims and application implications have been carefully revised to ensure they are fully supported by the experimental data. • The manuscript was streamlined to remove repetition, reduce length, and present the main findings more clearly. • Statistical rigor was strengthened by including 95% confidence intervals, effect sizes, and variation metrics for sensitivity, limits of detection, and calibration data. • Results and discussion sections were reorganized to improve readability and better highlight key outcomes. • The overall manuscript now provides clearer, more transparent, and verifiable evidence to support the conclusions. The development of scalable, high-performance biosensing platforms is critical for rapid diagnostics and environmental monitoring. In this study, aluminium interdigitated electrodes (Al-IDEs) were fabricated via standard photolithography and aluminium sputtering on thermally oxidized silicon substrates to achieve precise geometries (∼10 µm finger width, ∼5 µm inter-finger spacing). Optical microscopy confirmed uniform pattern fidelity, while electrical characterization across 0–1 V demonstrated reproducible current outputs of 0.632–0.671 nA at 1 V with <3.1% device-to-device variation. Electrochemical evaluation in buffer solutions revealed clear pH responsiveness, with current values of 2.291 nA (pH 4), 1.322 nA (pH 7), and 2.027 nA (pH 10), attributed to ionic mobility and electric double-layer modulation. Surface functionalization markedly enhanced sensing performance. GO/PANI-modified IDEs achieved the highest H⁺ sensitivity of 5.8 µA/pH (95% CI: 5.44–6.16), while APTES- and MPTES-functionalized electrodes enabled selective detection of NH₄⁺ and Na⁺, with sensitivities of 4.1 µA/pH (95% CI: 3.84–4.36) and 3.2 µA/pH (95% CI: 3.00–3.40), and limits of detection of 12 µM (95% CI: 11.2–12.8) and 25 µM (95% CI: 23.4–26.6), respectively. Selectivity indices of 8.5–12.5 confirmed reliable discrimination against K⁺, Ca²⁺, and Mg²⁺ interferents. The incorporation of confidence intervals (CI) validates the statistical robustness of these findings, ensuring reproducibility and reliability. Collectively, the results establish Al-IDEs as cost-effective, structurally consistent, and highly tunable electrochemical transducers, with strong potential for integration into next-generation biosensors for clinical, environmental, and industrial applications.