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 H2S amplification with a chemical reaction-mediated electrochemical signal-boosted system for H2S detection based on Cu-Mn(OH)2 hexagonal nanorings. The signal amplification is initiated by an electrocatalysis reaction that can grasp specific H2S substrates and further highly amplify electrochemical signals. Then, the unique chemical reaction is powered by copper ion and generates a large amount of electroactive CuxS products on the electrode surface, thus achieving the multiple amplification of H2S detection. Finally, the Cu-Mn(OH)2 loaded with plenty of electroactive CuxS can be captured on the electrode for further improving the electrochemical signal thus obtaining ultra-high sensitive determination of H2S. 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 H2S 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 H2S-related disease in clinical diagnosis.