Bimetal−organic framework-integrated electrochemical sensor for on-chip detection of H₂S and H₂O₂ in cancer tissues

Studies on the interaction between hydrogen sulfide (H₂S) and hydrogen peroxide (H₂O₂) in redox signaling motivate the development of a sensitive sensing platform for their discriminatory and dynamic detection. Herein, we present a fully integrated microfluidic on-chip electrochemical sensor for the online and simultaneous monitoring of H₂S and H₂O₂ secreted by different biological samples. The sensor utilizes a cicada-wing-like RuCu bimetal−organic framework with uniform nanorods architecture that grows on a flexible carbon fiber microelectrode. Owing to the optimized electronic structural merits and satisfactory electrocatalytic properties, the resultant microelectrode shows remarkable electrochemical sensing performance for sensitive and selective detection of H₂S and H₂O₂ at the same time. The result exhibits low detection limits of 0.5 μM for H₂S and 0.1 μM for H₂O₂, with high sensitivities of 61.93 μA cm⁻² mM⁻¹ for H₂S, and 75.96 μA cm⁻² mM⁻¹ for H₂O₂. The integration of this biocompatible microelectrode into a custom wireless microfluidic chip enables the construction of a miniature intelligent system for in situ monitoring of H₂S and H₂O₂ released from different living cells to differentiate between cancerous and normal cells. When applied for real-time tracking of H₂S and H₂O₂ secreted by colorectal cancer tissues, it allows the evaluation of their chemotherapeutic efficacy. These findings hold paramount implications for disease diagnosis and therapy.