Sandwich-type electrochemical immunosensor using dumbbell-like nanoparticles for the determination of gastric cancer biomarker CA72-4

• Published in: Talanta (Oxford) 2015-03, Vol.134, p.305-309
• Main Authors: Wu, Dan, Guo, Zhankui, Liu, Yixin, Guo, Aiping, Lou, Wanruo, Fan, Dawei, Wei, Qin
• Format: Article
• Language: English
• Subjects: Antibodies; Antibodies, Immobilized; Antigens, Tumor-Associated, Carbohydrate - blood; Biomarkers; Biomarkers, Tumor - blood; Biosensing Techniques; Cancer; Carbon - chemistry; Electrochemical Techniques; Electrodes; Ethylenediamines - chemistry; Gastric cancer biomarker CA72-4; Graphene; Humans; Hydrogen Peroxide - chemistry; Immunoassay; Immunosensor; Immunosensors; Limit of Detection; Metal Nanoparticles - chemistry; Metal Nanoparticles - ultrastructure; Nanoparticles; PtPd-Fe3O4 nanoparticles; Receiving; Reduced graphene oxide-tetraethylene pentamine (rGO-TEPA); Stomach Neoplasms - blood; Stomach Neoplasms - diagnosis; Stomach Neoplasms - immunology
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2014.11.025

A novel and sensitive nonenzymatic sandwich-type electrochemical immunosensor for the detection of gastric cancer biomarker CA72-4 was fabricated using dumbbell-like PtPd-Fe3O4 nanoparticles (NPs) as a novel kind of label. The signal amplification strategy, using the synergetic effect present in PtPd-Fe3O4 to increase the reduction ability of the NPs toward H2O2, improved the sensitivity of the immunosensor. The immunosensor was constructed by modifying glassy carbon electrode with reduced graphene oxide-tetraethylene pentamine (rGO-TEPA) for effective immobilization of primary anti-CA72-4 antibody (Ab1). Secondary anti-CA72-4 antibody (Ab2) was adsorbed onto the PtPd-Fe3O4 NPs. The proposed immunosensor displayed a wide linear range (0.001–10U/mL) with the low detection limit (0.0003U/mL). The immunosensor was evaluated for serum samples, receiving satisfactory results. Therefore, the immunosensor possesses excellent clinical value in cancer screening as well as convenient point-of-care diagnostics. [Display omitted] •A novel electrochemical sensor for the determination of CA72-4 is developed.•rGO-TEPA and PtPd-Fe3O4 are used as electrode materials and labels.•PtPd-Fe3O4 shows highly electrocatalytic activity due to synergetic effect.•The sensor has a wide linear range, low detection limit and good stability.