Laser-Induced Fabrication of Binder-Free Hierarchical Ru-Ir Bimetallic Microstructures for Sensitive Dual-Range Non-Enzymatic Glucose Detection

Developing efficient, non-enzymatic glucose sensors is crucial for overcoming the stability and environmental limitations of conventional enzymatic devices. In this work, a series of ruthenium-based bimetallic microstructures (Ru–Ir, Ru–Pt, Ru–Au DMF, and Ru–Au NPs) were successfully fabricated on glass substrates using a mask-free, two-stage laser-induced chemical liquid-phase deposition (LCLD) technique. Among the prepared materials, the binder-free Ru–Ir electrode exhibited the highest electrocatalytic activity toward glucose oxidation in an alkaline medium. Characterization by SEM, EDX, and XRD revealed a highly developed hierarchical surface morphology with distinct metallic phases. Chronoamperometric measurements performed at an operating potential of 0.45 V (vs. Ag/AgCl) demonstrated that the Ru–Ir sensor possesses a dual-range linear calibration—0.5–3000 μM and 3000–12,500 μM—with sensitivities of 0.027 and 0.014 μA μM−1 cm−2, respectively. The limit of detection was determined to be 58.1 nM. This improved performance and dual-range linearity are highly likely attributed to the abundance of electroactive sites provided by the hierarchical architecture and a synergetic effect between Ru and Ir that accelerates surface-controlled glucose dehydrogenation. Furthermore, the Ru–Ir sensor demonstrated negligible cross-sensitivity toward common interferents, an electrode-to-electrode RSD of 2.33% (n = 5), and remarkable long-term stability, retaining over 85% of its initial response after 30 days. Overall, the two-stage LCLD procedure provides a mask-free, binder-free, and direct-write route for fabricating bimetallic electrodes under ambient conditions.