An "off-on" electrochemiluminescence aptasensor for microcystin-LR assay based on the resonance energy transfer from PTCA/NH₂-MIL-125(Ti) to gold nanoparticles

A novel "off-on" electrochemiluminescence (ECL) aptasensor based on ECL resonance energy transfer (RET) system from 3,4,9,10-perylenetetracar-boxylic acid/the metal-organic frameworks NH₂-MIL-125(Ti) (PTCA/NH₂-MIL-125) to Au nanoparticles (Au NPs) was put forward for microcystin-LR (MC-LR) assay. The electrochemiluminescence (ECL) emission spectra of PTCA/NH₂-MIL-125 show excellent spectral overlap with the UV-vis absorption spectrum of Au NPs. A linear response ranging from 10 fM (9.95 × 10⁻⁶ μg L⁻¹) to 0.1 μM (99.5 μg L⁻¹) was obtained, and the detection limit was 3.6 fM (3.58 × 10⁻⁶ μg L⁻¹) under optimal conditions at a potential of − 1.6 V (S/N = 3). Besides, the prepared ECL-RET MC-LR aptasensor exhibited good selectivity and stability.