The Confinement of Multiple Interfaces for Self‐Enhanced Photoelectrochemical and Electrochemiluminescence Dual‐Mode Biosensor

Biosensor plays a vital role in the analysis of pesticide residues, but the efficiency of sensing substrate is still a challenging. In this work, a multiple interface-based confinement strategy was demonstrated to simultaneously boost photoelectrochemical (PEC) and electrochemiluminescence (ECL) responses for acetamiprid detection accompanying with intramolecular DNA wheel nanostructures as signal amplification and PtPd-CoSnO₃ nanocubes as quenchers. Due to the confinement effect and multiple light reflections between CdS nanoparticles, SiO₂, and NaYF₄:Yb/Tm, CdS@SiO₂@NaYF₄:Yb/Tm core-shell nanocomposites possessed fast electron transfer and high light utilization, yielding enhanced PEC and ECL responses. The peroxidase-mimicking catalytic precipitation property and the broad-spectrum absorption of PtPd-CoSnO₃ nanocubes realized the simultaneous quench of PEC and ECL signals. Impressively, nicking endonuclease (NEase)-based DNA wheel nanostructures were quite beneficial to the low background interference and the efficient dynamic signal amplification. As a result, the proposed dual-mode biosensor achieved acetamiprid detection in a range of 1 fM to 1 nM with detection limit of 0.31 fM (PEC detection) and 0.42 fM (ECL detection). Moreover, satisfactory results were also obtained in the analysis of real samples with remarkable selectivity, stability and reproducibility, establishing the biosensor as a dependable approach for precise pesticides detection.