Multisignal Conversion Electrochemiluminescence Strategy Based on Nanozyme-Enhanced Nitrogen-Vacancy/Oxygen-Doped g-CN for the Detection of Cholesterol.

The high and stable signal intensity of electrochemiluminescence (ECL) is crucial for establishing highly sensitive ECL biosensors. Here, nitrogen-vacancy/oxygen-doped carbon nitride (OCNNV-650) was first used as an ECL emitter, significantly improving the low ECL activity and poor dispersion of graphitic carbon nitride (g-CN) through a molecular engineering strategy. It is particularly noteworthy that FeO@MoS peroxidases, as coreaction accelerators, are the key to achieving the first and last "signals on", promoting the production of more SO and even promoting the production of •OH radicals when cholesterol is electrocatalyzed to produce HO. The intermediate "signal off" is induced by nitrogen and sulfur codoped carbon dots (NS-CDs), which significantly reduce the ECL detection background by hindering the electron transfer between SO and SO. The optimized sensor detects 0.31 μM cholesterol with a broad detection range (0.1 μM-0.1 mM). The "on-off-on" strategy facilitates multipathway ECL emission of OCNNV-650 with high and stable signal intensity, presenting a new method to develop ECL biosensors with high sensitivity and real-time accurate detection for disease prevention and human health care.