An electrochemical immunosensor for simultaneous multiplexed detection of neuron-specific enolase and pro-gastrin-releasing peptide using liposomes as enhancer

In this work, a multiplex immunoassay was constructed based on the amplification strategy using the liposomes which contained different electrochemical active molecule as singal enhancer for the simultaneous quantify neuron-specific enolase (NSE) and pro-gastrin-releasing peptide (ProGRP). First of all, the liposomes encapsulated with electrochemical active molecules, ascorbic acid (AA) and uric acid (UA), were prepared as immune labels respectively. With the sandwich type immunoreactions format, the marker entrapped liposomes labeled secondary antibodies were employed to form the immune complex, which were then destroyed by the addition of surfactant and the entrapped marker was electrochemically detected using carbon nanotubes modified electrodes. Based on the new signal amplification strategy, the immunoassay could simultaneous multiplexed detected ProGRP and NSE in the concentration range from 50 to 1000 pg/mL and 5.0 to 100 ng/mL, respectively. In conclusion, the multiplex immunoassay can offer higher sample throughput, less sample consumption, shorter assay time and lower cost than the traditional parallel single-analyte immunoassay. (C) 2011 Elsevier Ltd. All rights reserved.