An ultrasensitive label-free electrochemical immunosensor was fabricated for quantitative detection of carcinoembryonic antigen (CEA). The nitrogen, sulphur co-doped graphene quantum dots (N, S-GQDs) and gold polyaniline (Au-PANI) were synthesized by a simple hydrothermal and interfacial polymerization methods. Subsequently, N, S-GQDs decorated Au-PANI (N, S-GQDs@Au-PANI) were successfully prepared via a self-assembly approach. This novel nanocomposite N, S-GQDs@Au-PANI, increases the electrode surface area in nanoscale dimension, and also provides a highly stable and biocompatible matrix for the convenient conjugation of antibody, thus providing a immunoassay platform with an excellent efficiency. Monoclonal antibodies of carcinoembryonic antigen (anti-CEA) are effectively immobilized on the N, S-GQDs@Au-PANI to fabricate the impedimetric immunosensor. Under optimal conditions, the proposed immunosensor was used for the detection of CEA with wide linear range from 0.5 to 1000 ng mL-1 with a low detection limit of 0.01 ng mL-1. The high selectivity and stability made such immunosensor detect CEA in human serum with satisfactory results. All data indicated that, as prepared N, S-GQDs@Au-PANI nanocomposite is a promising electrochemical sensing platform for the detection of biological molecules.

Label-free impedimetric immunosensor based on N, S-GQDs decorated Au-PANI for selective detection of carcinoembryonic antigen

2019 Spring National Meeting

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