Detection of acetylcholinesterase based on ECL resonance energy transfer between luminol and gold nanoparticle decorated covalent organic framework

Covalent organic framework (COF) materials exhibit potential application in electrochemical sensing and attract increasing research interests. In this study, a novel signal-off mode electrogenerated chemiluminescence (ECL) sensor based on gold nanoparticle decorated COF (Au@COF) composite was developed. The oxidation of luminol was promoted at ferrocene (Fc) modified electrode to generate strong anodic ECL signal. The resonance energy transfer (RET) between luminol ECL and Au@COF composite could inhibit ECL emission. The acetylcholinesterase (AChE) aptamer connected Au@COF composite was immobilized onto the electrode through DNA hybridization to construct ECL-RET system. The specific recognition between AChE and its aptamer could release Au@COF composite from the electrode surface to block the ECL-RET process and restore the ECL signal. As a result, an ‘‘off-on’’ type ECL sensor was constructed and used to detect AChE in the range of 0.5 nM-1 μM, with a detection limit of 1.7 × 10 -10 mol/L (3σ). The sensor has high sensitivity and good stability, indicating that COF composite has attractive potential application in ECL sensing field.