Simple and ultrasensitive solid-state electrochemiluminescence sensor based on g-C3N4 and Au NPs for detection of Doxorubicin

A simple and ultrasensitive solid-state electrochemiluminescence (ECL) sensor was developed for the detection of doxorubicin (DOX). The sensor was constructed by coating the electrode with graphitic carbon nitride (g-C3N4) and a complex substance called Au NPs@HAP@CS, which consists of Au nanoparticles (Au NPs), hydroxylaptite (HAP), and chitosan (CS). The luminescent reagent, g-C3N4, obtained from high temperature pyrolysis of melamine, produced a relatively sensitive but unstable ECL signal in a K2S2O8 solution (pH 8.0). The introduced Au NPs, with their high negative potential, enhanced electron transport and captured and store excess electrons injected into g-C3N4, thereby improving the ECL signal and its stability. The non-toxic green HAP, serving as a carrier of Au NPs, further enhanced the ECL signal, and the addition of CS improved the stability of the sensor. Under optimal conditions, the fabricated ECL sensor demonstrated sensitive determination of DOX, with a linear range of 5.0 × 10−15 ∼ 1.0 × 10−8 mol/L and a detection limit as low as 1.67 × 10−15 (S/N = 3). Notably, the resulting sensor exhibited good stability, high sensitivity, and reliable reproducibility, making it suitable for the detection of trace DOX in human serum.