An Ultrasensitive Chemiluminescence Biosensor for Carcinoembryonic Antigen Based on Autocatalytic Enlargement of Immunogold Nanoprobes

A sensitive flow injection chemiluminescence assay for carcinoembryonic antigen (CEA) detection based on signal amplification with gold nanoparticles (NPs) is reported in the present work. The sandwich system of CEA/anti-CEA/goat-anti-mouse IgG functionalized Au nanoparticles was used as the sensing platform. In order to improve detection sensitivity, a further gold enlargement step was developed based on the autocatalytic Au deposition of gold nanoprobes via the reduction of AuCl(4)(−) to Au(0) on their surface in the presence of NH(2)OH·HCl. AuCl(4)(−), which is a soluble product of gold nanoprobes, served as an analyte in the CL reaction for the indirect measurement of CEA. Under optimized conditions, the CL intensity of the system was linearly related to the logarithm of CEA concentration in the range of 100 pg·mL(−1) to 1,000 ng·mL(−1), with a detection limit of 20 pg·mL(−1).