Anchoring luminol based on TiC-mediated in situ formation of Au NPs for construction of an efficient probe for miRNA electrogenerated chemiluminescence detection.

An efficient electrogenerated chemiluminescence (ECL) nanoprobe (luminol-Au NPs-TiC) was constructed based on TiCTx MXene (TiC)-mediated in situ formation of Au NPs and anchoring luminol to fabricate a sensitive ECL biosensor for miRNA-155 detection. Herein, TiC with rich Ti vacancy defects was used as reducing agent, and Au NPs were generated in situ and anchored on the TiC (Au NPs-TiC). Moreover, the Au NPs-TiC composites were used as a carrier and provided a large number of sites for the efficient linking of luminol through Au-N bonds to form stable luminol-Au NPs-TiC. The immobilization of ECL emitters is a versatile strategy which not only shortens the electron transmission distance between luminol and electrode, but also provides naked catalytic predominated (111) facets of Au NPs with high electrocatalytic activity, significantly improving the ECL signal of luminol. Furthermore, a catalytic hairpin assembly (CHA) reaction was used, resulting in further amplification of the signal. As a result, the as-prepared ECL biosensor exhibited a linear range from 0.3 fM to 1 nM with a detection limit of 0.15 fM, and demonstrated high reliability of miRNA-155 detection even in human serum samples. The construction of a multifunctional ECL probe with excellent ECL emission opens a new chapter for the application of TiC in the field of bioanalysis. Herein, Au NPs were generated in situ and anchored on the TiC (Au NPs-TiC). Moreover, the Au NPs-TiC was used as a carrier and linked luminol through Au-N bonds to form a stable luminol-Au NPs-TiC nanoprobe. The strategy displayed versatility which not only shortened the electron transmission distance between luminol and the electrode, but also provided a catalytic surface with high electrocatalytic activity of Au NPs that significantly improved the ECL signal of luminol.