Ultrasensitive all-solid-state electrochemiluminescence platform for kanamycin detection based on the pore confinement effect of 0D g-C3N4 quantum dots/3D graphene hydrogel

Quests for stable and highly efficient electrochemiluminescence (ECL) emitters and a full understanding of the relation between the ECL emitter structure and its properties are a continual and active theme in the fields of ECL. In this work, an intense and stable ECL platform was achieved by encapsulating 0D graphite carbon nitride quantum dots (g-C3N4 QDs) into 3D graphene hydrogel via a facile hydrothermal approach. The architectures of the as-fabricated 0D g-C3N4 QDs/3D graphene hydrogel nanocomposites showed 4.3-fold ECL intensity relative to that of pure g-C3N4. This phenomenon was caused by a pore confinement effect, which could increase the electrochemical reaction efficiency because the pore channels could promote electron transfer and mass transport. The confinement effect could also localise a very large luminophore near the electrode surface, resulting in enhanced ECL emission. Moreover, the as-fabricated architecture ensured the stability of the g-C3N4 QDs in the ECL field due to the increased dispersibility. On the basis of the excellent ECL performances, a novel ECL biosensor was fabricated for highly selective and sensitive detection of kanamycin (KAN) with the assistance of an aptamer. The proposed ECL sensor can quantify KAN from 1 pM to 50 nM with a limit of detection of 0.33 pM. Such work offers an efficient design idea for achieving a high-performance ECL platform and provides new insight into developing and applying a g-C3N4-based ECL system.