Porous UiO-66-NH<sub>2</sub>-Mediated Enrichment and Immobilization of WO<sub>3–<i>x</i></sub> Quantum Dots for Enhanced Electrochemiluminescence Performance and Ultrasensitive Detection of miRNA-126
Zhenyu Wang, Zhenyu Wang, Xuemei Wang, Yuehan Xie, Jingjie Dai, Zonghua Wang, Zonghua Wang
Abstract
The excellent dispersibility of quantum dots (QDs) hinders their aggregation and makes them prone to nonradiative annihilation, thereby leading to weak and unstable electrochemiluminescence (ECL) signals. To address this limitation, this study employed a porous metal–organic framework (MOF, UiO-66-NH 2 ) material to achieve the enrichment and uniform immobilization of coreactant QDs (WO 3– x QDs), constructing a coreactant nanoreactor (WO 3– x QDs@UiO-66-NH 2 ). The high porosity of UiO-66-NH 2 not only significantly increased the local concentration of WO 3– x QDs on the electrode surface but also facilitated electron transfer through a spatial confinement effect, leading to substantial amplification of the ECL signal. Theoretical calculations revealed that oxygen vacancies in WO 3– x QDs reconstructed the interfacial reaction pathway through a bifunctional synergistic effect, further boosting ECL performance. Meanwhile, an Ru-AuNPs-H2 luminescent probe was synthesized via electrostatic interactions between negatively charged gold nanoparticles ((−)AuNPs) and Ru(bpy) 3 2+ . Furthermore, the catalytic hairpin assembly-mediated recognition mechanism enabled the recycling of target miRNA-126 and promoted electron transfer through structural transformation, ultimately achieving a significant enhancement of the ECL signal. Under the optimal conditions, the ECL biosensor exhibited a remarkably low detection limit of 1.0 × 10 –18 M for miRNA-126 and demonstrated excellent anti-interference performance and reliability in real sample detection. This work not only overcomes the limitations of QDs in solution but also further carries forward their advantage of a high reaction efficiency. The proposed assembly strategy provides a novel research approach and technical platform for the precise analysis of biomarkers, holding broad application prospects.