Research on the expression of miR-192-5p in extracellular vesicles of diabetic nephropathy based on ternary heterojunction/heterogeneous interface interlocking hydrogel ECL strategy

Herein, a novel electrochemiluminescence (ECL) biosensor was constructed based on a Nb 2 C/Nb 2 O 5 /ZnO QDs ternary heterojunction and heterogeneous interface interlocking (HII) hydrogel self-supporting electrode, which achieved sensitive and specific detection of miR-192-5p in extracellular vesicles (EVs) from diabetic nephropathy (DN)urine and serum samples. This Nb 2 C/Nb 2 O 5 /ZnO QDs heterojunction integrated the S-scheme heterojunction between Nb 2 O 5 and ZnO QDs with the Schottky junction between Nb 2 C and Nb 2 O 5 . On the one hand, Nb 2 O 5 acted as a bridging medium to drive directional migration of electrons and holes, which overcame the incomplete charge separation in traditional binary heterojunctions. On the other hand, Nb 2 C nanosheets provided directional electron transport channels and served as a coreactant reservoir, effectively promoting electron injection and exciting ZnO QDs to generate enhanced ECL signals at low voltage. Meanwhile the HII hydrogel electrode achieved dual electrical-ionic conductivity with excellent biocompatibility and stability, significantly boosting the ECL sensing performance. The Nb 2 C/Nb 2 O 5 /ZnO QDs heterojunction -HII hydrogel biosensor was used to detect miR-192-5p with a linear range of 1 fM–1 nM and a detection limit of 0.33 fM. Clinical detection results revealed miR-192-5p was upregulated in urinary EVs and downregulated in serum EVs of DN patients with disease progression. This biosensor enabled early, non-invasive and multidimensional DN diagnosis, providing a novel analytical strategy for precise DN detection and clinical application.