Surface plasmon resonance based immunosensor for the detection of the cancerbiomarker carcinoembryonic antigen

摘要

An immunoassay in optimised conditions with a highly sensitive surface plasmonresonance (SPR) based biosensor was developed for the detection of the cancerbiomarker carcinoembryonic antigen (CEA). Different formats of the immunoassaywere initially investigated on the surface of the gold sensor chip. A self-assembled monolayer (SAM) was formed on the gold chip using 11-mercaptoundecanoic acid (MUDA), before the immobilisation of the antibodies wasconducted. The assay was then formed in a direct capture and a sandwich assay.In order to increase the sensor signal the CEA antigen was incubated with thedetection/capture antibody before it was injected to the sensor chip surface andthe results were recorded in real-time using the Biacore 3000 instrument. Adetection limit of 3ngml-1 CEA was obtained with a dynamic detection range from3ngml-1 to 400ngml-1 with correlation coefficients of 1.00 and 0.99 for thesandwich and rabbit anti-mouse (RAM) capture assay. Kinetic data analysis wasperformed for the standard capture test and subsequently for the developedassays and Rmax showed an increase from 215 RU for the standard capture test to428 RU for the RAM-capture assay and 734 RU for the sandwich assay,respectively. The developed SPR immunosensor using the sandwich assay formatshowed high sensitivity and reproducibility for CEA detection which makes it apromising procedure for cancer biomarker analysis