Surface-enhanced molecularly imprinted electrochemiluminescence sensor based on Ru@SiO₂ for ultrasensitive detection...

A novel molecularly imprinted electrochemiluminescence (MIP-ECL) sensor based on Ru(bpy)₃²⁺-doped silica nanoparticles (Ru@SiO₂ NPs) is developed for highly sensitive detection of fumonisin B₁ (FB₁). Gold-nanoparticles (AuNPs), Ru@SiO₂ NPs with chitosan (CS) composites and a molecularly imprinted polymer (MIP) are assembled on a glassy carbon electrode (GCE) to fabricate an ECL platform step by step. AuNPs could greatly promote the ECL intensity and improve the analytical sensitivity according to the localized surface plasmon resonance (LSPR) and the electrochemical effect. In this surface-enhanced electrochemiluminescence (SEECL) system, AuNPs work as the LSPR source to improve the ECL intensity and Ru@SiO₂ NPs are used as ECL luminophores. In the phosphate buffer solution (PBS), the evident anodic ECL of Ru@SiO₂ on the above working electrode is observed in the presence of the template molecule fumonisin B₁ (FB₁), which could act as the coreactant of Ru@SiO₂ NPs due to the amino group of FB₁. When the template molecules were eluted from the MIP, little coreactant was left, resulting in an apparent decrease of ECL signal. After the MIP-ECL sensor was incubated in FB₁ solution, the template molecules rebound to the MIP surface, leading to the enhancement of ECL signal again. On the basis of these results, a facile MIP-ECL sensor has been successfully fabricated, which exhibited a linear range from 0.001 to 100ngmL^-1 with a detection limit of 0.35pgmL^-1 for FB₁. Moreover, the proposed MIP-ECL sensor displayed an excellent application in real samples.