Nickel Single-Atom Catalyst Boosts Electrochemiluminescence of Graphitic Carbon Nitride for Sensitive Detection of HBV DNA.

Owing to excellent catalytic activity, single-atom catalysts (SACs) have recently attracted considerable research interest in the electrochemiluminescence (ECL) field. However, the applications of SACs are mostly limited to conventional luminol ECL system. Hence, it is necessary to explore the application of SACs in more ECL systems. In this work, nickel single-atom catalysts (Ni SACs) were successfully applied in the graphitic carbon nitride (g-C 3 N 4 )-H 2 O 2 ECL system to significantly enhance its cathodic emission. Notably, g-C 3 N 4 acted not only as an ECL luminophore but also as a support to anchor Ni SACs. Ni SACs can significantly activate H 2 O 2 to produce abundant OH • radicals for enhancing the cathodic ECL emission of g-C 3 N 4 . Ni SACs-anchored g-C 3 N 4 (Ni SACs@g-C 3 N 4 ) had a 10-fold enhanced ECL intensity as compared to g-C 3 N 4 . Finally, the Ni SACs@g-C 3 N 4 -H 2 O 2 ECL system was developed to detect hepatitis B virus (HBV) DNA by incorporating an entropy-driven DNA walking machine-assisted CRISPR-Cas12a amplification strategy. The constructed biosensor exhibited excellent detection performance for HBV DNA with a limit of detection as low as 17 aM. This work puts forward a new idea for enhancing the cathodic ECL of g-C 3 N 4 -H 2 O 2 and expands the application of SACs in the ECL system.