MoS₂ QDs-MXene heterostructure-based ECL sensor for the detection of miRNA-135b in gastric cancer exosomes

Exosomes play an important role in the proliferation, adhesion and migration of cancer cells. In this study, we have developed a novel electrochemiluminescence (ECL) sensor based on MoS₂ QDs-MXene heterostructure and Au NPs@biomimetic lipid layer to detect exosomal miRNA. MoS₂ QDs-MXene heterostructure had been prepared as the luminescence probe. Ti₃C₂T_x MXene nanosheets possessed the large specific surface area, excellent flexibility and superior conductivity. MoS₂ QDs on the MXene nanosheets worked as the radiation center to generate strong ECL signal. Meanwhile, Au NPs with biomimetic lipid layer have been modified on the electrode, which retained the lipid dynamics and excellent antifouling property. When miRNA-135b was recognized on the Au NPs@biomimetic lipid layer, MoS₂ QDs-MXene heterostructure was linked on the electrode and further extended the outer Helmholtz plane. As a result, the self-luminous Faraday cage-mode sensing system has been used to detect miRNA-135b from 30 fM to 20 nM with a detection limit of 10 fM. Furthermore, gastric cancer exosomal miRNA in the ascites of clinical patients has been detected successfully. The sensing system can be served as a versatile platform with huge application potential in the field of exosome detection.