N-doped TiO/TiC-driven self-photocatalytic molecularly imprinted ECL sensor for sensitive and steady detection of dexamethasone.

The conventional luminol-based electrochemiluminescence (ECL) biosensor suffers from hampered signal stability due to the self-decomposition of the HO co-reactant. Here, we propose an N-doped TiO/TiC heterojunction driven self-photocatalytic platform for ECL signal amplification and then combine it with molecular imprinting technology for sensitive and steady detection of dexamethasone (DXM). Unlike traditional cases involving specific catalysts or external electron injection, the initial luminescence of luminol in this new system is utilized as the excitation light of N-doped TiO/TiC photocatalyst to promote the conversation of dissolved oxygen to HO, supplying more co-reactants to improve ECL of luminol in turn. Thanks to the heterojunction and self-photocatalytic cyclic amplification, this molecularly imprinted ECL sensor exhibits a wide linear range (1.0 × 10-1.0 × 10 μg mL) and a low detection limit, as well as excellent anti-interference capability, sensitivity, and stability. This work contributes to more reliable and steady detection of DXM and brings new insights into developing exogenous co-reactant-free self-enhancement ECL models for biosensor applications.