Nano-hybrid luminophores of Ti₃C₂T_X quantum dots-gold nanoparticles based on in situ generation for sensitive electrochemiluminescence biosensing

Nanomaterial-derived quantum dots (QDs) are excellent electrochemiluminescence (ECL) luminophores and play an important role in optical sensing due to their excellent water solubility, good biocompatibility and tunable molecular size. In this work, a novel strategy was designed to form nano-hybrid Ti₃C₂ QDs-AuNPs in situ as a luminophore based on the unique reducibility of Ti₃C₂ QDs, which showed remarkable and stable ECL performance. Here, AuNPs were formed in situ without the addition of reducing agents and stabilizers, leading to threefold enhancement of the ECL signal of Ti₃C₂ QDs due to their excellent charge transfer capability. Meanwhile, Ti₃C₂ QDs-AuNPs with abundant Ti atoms also acted as recognition units. Through skillful combination with hybridization chain reaction (HCR) to expose more phosphate, an ECL platform was constructed to detect polynucleotide kinase (PNK) with good specificity and sensitivity. A lower limit of detection limit of 2.7×10⁻⁵ U mL⁻¹ was achieved, with a wide linear relationship ranging from 0.0001 to 10 U mL⁻¹. This novel strategy provides a guide for the application of nano-hybrid Ti₃C₂ QDs-AuNPs as a luminophore in the field of ECL bioanalysis. Graphical abstract: Novel in situ-formed nano-hybrid Ti₃C₂ QDs-AuNPs were prepared as a luminophore, with threefold enhancement of the ECL signal of Ti₃C₂ QDs. [Figure not available: see fulltext.]