Electrochemical sensor for hydrogen sulfide detection using electrocatalysis-assisted amplification and chemical...

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 Cu_xS products on the electrode surface, thus achieving the multiple amplification of H₂S detection. Finally, the Cu-Mn(OH)₂ loaded with plenty of electroactive Cu_xS 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.