Bimetal-organic framework-integrated electrochemical sensor for on-chip detection of HS and HO in cancer tissues.

Studies on the interaction between hydrogen sulfide (HS) and hydrogen peroxide (HO) 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 HS and HO 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 HS and HO at the same time. The result exhibits low detection limits of 0.5 μM for HS and 0.1 μM for HO, with high sensitivities of 61.93 μA cm mM for HS, and 75.96 μA cm mM for HO. 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 HS and HO released from different living cells to differentiate between cancerous and normal cells. When applied for real-time tracking of HS and HO secreted by colorectal cancer tissues, it allows the evaluation of their chemotherapeutic efficacy. These findings hold paramount implications for disease diagnosis and therapy.