Efficient Au nanocluster@Ti₃C₂ heterostructure luminophore combined with Cas12a for electrochemiluminescence detection of miRNA

Gold nanoclusters (Au NCs) are potential electrochemiluminescence (ECL) emitters that have been increasingly studied in ECL sensing due to their excellent biocompatibility and electrochemical properties. However, their small size is not conducive to further separation and immobilization, resulting in their low ECL intensity. In this work, a new strategy was designed to form heterostructure Au NCs@Ti₃C₂ in situ as a luminophore based on the unique reducibility of Ti₃C₂, which greatly enhanced the ECL intensity. Here, Au NCs are firmly anchored on the surface of Ti₃C₂ through O atoms, and Au-O-Ti acts as the connection between Au NCs and Ti₃C₂. In addition, Ti₃C₂ with good conductivity is used as the carrier to increase the loading of Au NCs. Through skilful combination with CHA and the lateral cutting characteristics of CRISPR-Cas12a, an ECL biosensor was constructed to detect miRNA-155 with good specificity and sensitivity. The linear range was from 0.1 fM to 1.0 nM with a detection limit as low as 35.7 aM. This research has laid a solid foundation for the development of high efficiency Au NC luminophores and sensitive ECL platforms for clinical and biological analysis.