Novel samarium-based metal-organic frameworks with antenna effect-induced electrochemiluminescence for acetamiprid assay

Abstract

Lanthanide metal-organic frameworks (Ln-MOFs) have emerged as promising electrochemiluminescence (ECL) luminophores on account of their distinctive luminescence performances. However, currently reported Ln-MOFs-based ECL luminophores are mainly limited to terbium-based MOFs (Tb-MOFs) and europium-based MOFs (Eu-MOFs). This work innovatively developed samarium-based MOFs (Sm-MOFs) as ECL luminophores. Sm-MOFs were prepared via hydrothermal method with Sm^3 + as metal node and 1,3,5-benzenetricarboxylic acid (H₃BTC) as organic ligand. H₃BTC as “antenna” transferred energy to Sm³⁺ through antenna effect, enabling Sm-MOFs to emit brilliant cathode ECL signal with persulfate (S₂O₈^2-) as coreactant. Bismuth sulfide (Bi₂S₃) acted as signal regulator to remarkably quench the ECL emission from Sm-MOFs through ECL resonance energy transfer (ECL-RET). Using acetamiprid (ACE) as the target detection model, the ECL luminophores Sm-MOFs cleverly coupled signal regulator Bi₂S₃ and enzyme-free triple amplification strategy of hybridization chain reaction (HCR), catalytic hairpin assembly (CHA), and DNAzyme walker to fabricate an ECL biosensor. The limit of detection (LOD) was as low as 4.58 fM. This work not only exploited novel Ln-MOFs-based ECL luminophores and their application in ECL field, but also built an enzyme-free multiple amplification strategy for highly sensitive assay of ACE.