摘要

The shortened distance between luminophor and coreactant can effectively enhance luminous efficiency in electrochemiluminescence (ECL) system owing to the improvement of electron transfer rate. Here, a novel sandwich-type ECL immunosensor based on N-(aminobutyl)-N-(ethylisoluminol) (ABEI) as luminophor was constructed by integrating hollow gold nanoparticles (HAuNPs), L-cysteine (L-Cys) and ferrocene (Fc) in a complex for multiple signal amplification. The HAuNPs with large specific surface areas and superior conductivity were first used as scaffolds to load abundant coreactant L-Cys, aiming to further assemble catalyzer Fc stably. Through host-guest recognition, the beta-cyclodextrin (beta-CD) functionalized ABEI thus subsequently decorated on Fc, bringing in shortened distance between luminophor ABEI and coreactant L-Cys with high ECL signal. Moreover, the catalyzer Fc and HAuNPs could dramatically promote decomposition of another coreactant H2O2 to produce abundant superoxide radical (O-2(center dot-)) and hydroxyl radical (OH center dot) for further signal amplification. Taking beta 2-microglobulin (beta 2 M) as model analyte, the developed immunosensor exhibited a superior performance for detection beta 2 M in the range of 1.0 x 10(-3) 1.0 x 10(3) ngmL(-1) with a detection limit of 2.6 x 10(-1) pg mL(-1). The developed strategy realized solid-state ECL detection and multiple ECL signal amplification, providing a novel sensitive detection method for beta 2 M, which may show a great promise for the clinical application.