An electrochemiluminescence immunosensor based on Ag-Ti₃C₂ MXene and CNNVs with multiple signal amplification...

In electrochemical immunoassays, great breakthroughs have been made in ultrasensitive detection of tumor markers by amplifying signals with coreaction accelerators. Herein, carbon nitrides with nitrogen vacancies (CNNVs) are proposed as emitter, due to the introduction of nitrogen vacancies this emitter has better ECL efficiency, the phenomena of interface electron transfer and electrode passivation are improved. At the same time, it can also promote the electrochemical reduction of coreactant, making it an attractive and potential emitter. The electrode was modified with Ag-Ti₃C₂ MXene. It not only accelerates electron transfer and increases the effective working area of the electrode, but also acts as a coreaction accelerator to promote the electrochemical reduction of the coreactant K₂S₂O₈, resulting in a strong ECL signal. The immunosensor showed a good linear relationship in the range of 10^-5-100 ng/mL with a detection limit of 0.36 fg/mL. In addition, the excellent properties of good specificity and ultra-high stability provide an effective method for ultra-sensitive immunoassays.