Facile and feasible conductometric immunoanalytical assay for alpha-fetoprotein using platinum-functionalized graphitic carbon nitride nanosheets

A simple and feasible conductometric immunoanalytical method was developed for the sensitive detection of a liver cancer biomarker (alpha-fetoprotein, AFP) on an interdigitated comb-like transducer, using platinum (Pt)-functionalized graphitic carbon nitride (g-C 3 N 4 ) nanosheets. To construct suc...

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Bibliographic Details
Published in:Analytical methods 2018-10, Vol.1 (4), p.4886-4893
Main Authors: Li, Ling, Guo, Wuhua, Lin, Yao, Tang, Dianping, Liu, Jingfeng
Format: Article
Language:English
Subjects:
Antibodies
Biomarkers
Carbon
Carbon nitride
Coated electrodes
Electrodes
Enzyme-linked immunosorbent assay
Ethylene glycol
Hydrogen peroxide
Immobilization
Immunoassay
Immunosensors
Iodine
Liver
Liver cancer
Nanoparticles
Nanosheets
Platinum
Reduction
Sodium chloride
α-Fetoprotein
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Summary:A simple and feasible conductometric immunoanalytical method was developed for the sensitive detection of a liver cancer biomarker (alpha-fetoprotein, AFP) on an interdigitated comb-like transducer, using platinum (Pt)-functionalized graphitic carbon nitride (g-C 3 N 4 ) nanosheets. To construct such an immunosensing platform, platinum nanoparticles were initially loaded on the g-C 3 N 4 nanosheets by the aid of a ethylene glycol reduction method. Thereafter, the as-prepared Pt-g-C 3 N 4 nanohybrids were used as the affinity support for the immobilization of anti-AFP antibodies on the interdigitated electrode. Upon addition of AFP, the analyte reacted with the immobilized antibody to form the antigen-antibody immunocomplex, which was coated on the surface of the modified electrode, thereby partly decreasing the electrocatalytic efficiency of Pt-g-C 3 N 4 towards the reduction of hydrogen peroxide (H 2 O 2 ) in the presence of iodine ions (I − ). The variation in the local conductivity by iodine ions could be detected by using an external conductometer on the basis of the Pt-g-C 3 N 4 electrocatalytic reaction in 10 mM phosphate buffer (pH 6.5) containing 80 μM H 2 O 2 , 50 mM KI and 0.1 M NaCl. Under optimum conditions, the immunosensor exhibited good conductometric responses for the detection of AFP within the dynamic linear range of 0.1-100 ng mL −1 at a detection limit of 0.097 ng mL −1 . The strong attachment of anti-AFP antibodies to the Pt-g-C 3 N 4 brought good repeatability and intermediate precision down to ±12.7%. Importantly, no significant differences at the 0.05 significance level were encountered for the analysis of 12 human serum samples between the developed immunoassay and human AFP ELISA kit for AFP determination. A conductometric immunoanalytical method was developed for the sensitive detection of the liver cancer biomarker (alpha-fetoprotein, AFP), using platinum (Pt)-functionalized graphitic carbon nitride (g-C 3 N 4 ) nanosheets..
ISSN:1759-9660
1759-9679
DOI:10.1039/c8ay01789a