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A sensitive label-free immunosensor for detection α-Fetoprotein in whole blood based on anticoagulating magnetic
Tingting Xu1, Bo Chi2, Fan Wu3
1State Key Laboratory of Materials-Oriented Chemical Engineering, College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, China; National and Local Joint Engineering Research Center of Biomedical Functional Materials, Jiangsu Key Laboratory of Biofunctional Materials, College of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210023, China.
Abstract:
Accurate values of tumor markers in blood play an especially important role in the diagnosis of illness. Here, based on the combination of three techniques include anticoagulant technology, nanotechnology and biosensing technology, a sensitive label-free immunosensor with anti-biofouling electrode for detection α-Fetoprotein (AFP) in whole blood was developed by anticoagulating magnetic nanoparticles. The obtained products of Fe3O4-ɛ-PL-Hep nanoparticles were characterized by fourier transform infrared (FT-IR) spectra, transmission electron microscopy (TEM), ζ-potential and vibrating sample magnetometry (VSM). Moreover, the blood compatibility of anticoagulating magnetic nanoparticles was characterized by in vitro coagulation tests, hemolysis assay and whole blood adhesion tests. Combining the anticoagulant property of heparin (Hep) and the good magnetism of Fe3O4, the Fe3O4-ɛ-PL-Hep nanoparticles could improve not only the anti-biofouling property of the electrode surface when they contact with whole blood, but also the stability and reproducibility of the proposed immunosensor. Thus, the prepared anticoagulating magnetic nanoparticles modified immunosensor for the detection of AFP showed excellent electrochemical properties with a wide concentration range from 0.1 to 100ng/mL and a low detection limit of 0.072ng/mL. Furthermore, five blood samples were assayed using the developed immunosensor. The results showed satisfactory accuracy with low relative errors. It indicated that our developed immunoassay was competitive and could be potentially used for the detection of whole blood samples directly.