Multiplexed detection of two proteins by a reaction kinetics-resolved chemiluminescence immunoassay strategy

A multiplexed immunoassay method was proposed for the sequential detection of two proteins in a single run based on a novel chemiluminescence (CL) reaction kinetics-resolved strategy. This method was established using acridinium ester (AE) and alkaline phosphatase (ALP) as the signal probes due to the significant difference in their CL reaction kinetics characteristics. Mouse IgG (MIgG) and mouse IgM (MIgM) were detected as the model analytes with a competitive immunoassay format. AE and ALP were used to tag goat anti-mouse IgG and rabbit anti-mouse IgM, respectively, to form two immunocomplexes. The two CL reactions with flash type and glow type kinetics characteristics were triggered simultaneously by adding the coreactants, then the CL signals from the two reactions were recorded after 0.2 s and 500 s of the reaction triggering, respectively. The multiplexed CL immunoassay provided a wide range of 0.50-200 ng mL(-1), with a low detection limit of 0.16 ng mL(-1) (S/N = 3) for both MIgG and MIgM. Additionally, no obvious signal overlap was observed in the multiplexed immunoassay. The proposed method was successfully applied for the detection of MIgG and MIgM levels in mouse serums, and the results were in good agreement with those from the reference ELISA method. We anticipate that it can be used in some other areas such as drug screening, food safety, environment monitoring and clinical diagnosis.