Au nanoparticle plasmon-enhanced electrochemiluminescence aptasensor based on the 1D/2D PTCA/CoP for diclofenac assay

The combination of localized surface plasmon resonance (LSPR) and electrochemiluminescence (ECL) can be an effective way to amplify the signal intensity. In this work, an ECL aptasensor with 3,4,9,10-perylenetetracarboxylic acid-decorated cobalt phosphate (denoted as PTCA/CoP) as the ECL emitter and Au nanoparticles (NPs) as plasma was proposed for diclofenac assay. The prepared PTCA/CoP with special 1D/2D structure exhibited good ability and excellent ECL performance. The diclofenac aptamer acted as a bridge to link the PTCA/CoP and Au NPs; thus, the ECL performance of PTCA/CoP was greatly improved due to the plasma effect of Au NPs. Besides, it was found that the ECL signal of the aptasensor was obviously quenched by the introduction of diclofenac, which might be due to the transformation from the LSPR process to the resonance energy transform (RET) process. Under optimal conditions, the difference of ECL intensity was negatively correlated with the concentration of diclofenac in the range 0.1 pM to 10 μM with a low detection limit of 0.072 pM at the potential of -1.8 V vs. Ag/AgCl (S/N = 3). The aptasensor was proved to be suitable for the detection of diclofenac in real samples, suggesting its great practicability.