Electrochemical sensor for hydrogen sulfide detection using electrocatalysis-assisted amplification and chemical reaction-mediated signal enhancement.

An ultrasensitive electrochemical biosensing platform has been designed by combining electrocatalysis-assisted HS amplification with a chemical reaction-mediated electrochemical signal-boosted system for HS detection based on Cu-Mn(OH) hexagonal nanorings. The signal amplification is initiated by an electrocatalysis reaction that can grasp specific HS substrates and further highly amplify electrochemical signals. Then, the unique chemical reaction is powered by copper ion and generates a large amount of electroactive CuS products on the electrode surface, thus achieving the multiple amplification of HS detection. Finally, the Cu-Mn(OH) loaded with plenty of electroactive CuS can be captured on the electrode for further improving the electrochemical signal thus obtaining ultra-high sensitive determination of HS. The established electrochemical biosensing platform displays a wide analytical range of 0.1 μM to 265 μM with a low detection limit of 0.096 μM. The satisfactory selectivity allows the electrochemical sensor to distinguish HS from other interfering substances without any complicated pretreatment, even in complex tumor cell samples. Thus, our designed electrocatalysis-assisted amplification strategy offers a powerful analysis toolkit for the early determination of HS-related disease in clinical diagnosis.