A chitosan-Au-hyperbranched polyester nanoparticles-based antifouling immunosensor for sensitive detection of carcinoembryonic antigen

Analysts are always interested in finding new functional nanomaterials and devices with good properties for electrochemical sensor applications. In this paper, hyperbranched polyester nanoparticles with carboxylic acid functional groups (HBPE–CA NPs) were synthesized and combined with chitosan wrapped around Au nanoparticles (CS–Au NPs) to prepare a novel and sensitive electrochemical immunosensor by adsorption of carcinoembryonic antibody (anti-CEA) on the (HBPE–CA)/CS–Au NPs modified glass carbon electrode (GCE). Under the optimized conditions, the proposed immunosensor displayed a good amperometric response to carcinoembryonic antigen (CEA). Moreover, based on the antibiofouling properties, the immunosensor could be used for the direct detection of CEA in whole blood, and exhibited a wide detection range (1–107 fg mL−1), and a low detection limit of 0.251 fg mL−1 (signal/noise = 3). Control experiments were also carried out by using ascorbic acid (AA), uric acid (UA), human immunoglobulin G (IgG), BSA and glucose in the absence of CEA. The good stability and repeatability of this immunosensor were also proven. Importantly, the results of the detection of clinical whole blood specimens with the proposed immunosensor showed good consistency with the data determined by enzyme-linked immunosorbent assay (ELISA) in serum samples. Furthermore, the developed immunosensor could provide a promising immunoassay strategy for clinical applications, since the values we measured in whole blood directly are likely closer to the real values.