Efficient Al–H₃NTB-MOG ECL Emitter with Self-Enhanced and AIECL Performance for Ultrasensitive Sensing of miRNA-141 Combined with a Y-Shaped Multiregion Dual-Drive DNA Walker

In this work, using Al-H₃NTB-MOG with self-enhanced and aggregation-induced electrochemiluminescence (AIECL) performance as an efficient emitter, a biosensor based on a Y-shaped multiregion dual-drive DNA walker was constructed for the sensitive detection of miRNA-141. Notably, 4,4',4″-nitrilotribenzoic acid (H₃NTB) was selected as the luminescent ligand with self-enhanced ECL property as the co-reactive tertiary amine in its structure. Al³⁺ served as a central ion to coordinate with H₃NTB to form a three-dimensional porous gel structure, which restricted internal rotation and vibration of the benzene molecules and exhibited an excellent AIECL property. More interestingly, <i>N</i>-2-hydroxyethylpiperazine-<i>N</i>'-ethane-sulfonic acid (HEPES) was chosen as the system buffer, which could not only stabilize the test environment but also play a co-reaction compensation role to compensate for the consumption of the co-reactive groups in the ECL process, then significantly resulting in better stability of ECL response. Besides, an efficient dynamic signal amplification system was established based on the synergistic effect of rolling cycle amplification (RCA) process and ionic cleavage at both ends of the Y-shaped DNA nanostructure assembled by the catalytic hairpin self-assembly (CHA) reaction. Specifically, two long DNA chains with abundant recognition regions were formed by the RCA reaction as a dual-drive DNA walker, which could simultaneously walk along the predesigned tracks and shear the specific sites from two directions, effectively improving the signal amplification efficiency. In that way, the constructed biosensor realized the detection of miRNA-141 from 10 aM to 1 nM range with a detection limit as low as 6.48 aM.