Viologen-functionalized single-walled carbon nanotubes as carrier nanotags for electrochemical immunosensing. Application to TGF-β1 cytokine

• Published in: Biosensors & bioelectronics Vol. 98; pp. 240 - 247
• Main Authors: Sánchez-Tirado, Esther, Arellano, Luis M., González-Cortés, Araceli, Yáñez-Sedeño, Paloma, Langa, Fernando, Pingarrón, José M.
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 15-12-2017
• Subjects: Biosensing Techniques; Cytokine; Electrochemical immunosensor; Electrochemical Techniques; Humans; Immunoassay; Nanotubes, Carbon - chemistry; Saliva; Transforming Growth Factor beta1 - chemistry; Transforming Growth Factor beta1 - genetics; Transforming Growth Factor beta1 - isolation & purification; Transforming growth factor β1; Viologen; Electrochemical immunosensor; Viologen; Transforming growth factor β1; Saliva; Cytokine
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2017.06.063

Viologen-SWCNT hybrids are synthesized by aryl-diazonium chemistry in the presence of isoamyl nitrite followed by condensation reaction of the resulting HOOC-Phe-SWCNT with 1-(3-aminoethyl)-4,4′-bipyridinium bromine and N-alkylation with 2-bromoethylamine. The V-Phe-SWCNT hybrids were characterized by using different spectroscopic techniques (FT-IR, Raman, UV–vis), TGA and Kaiser test. Viologen-SWCNTs were used for the preparation of an electrochemical immunosensor for the determination of the transforming growth factor β1 (TGF-β1) cytokine considered as a reliable biomarker in several human diseases. The methodology involved preparation of V-Phe-SWCNT(-HRP)-anti-TGF conjugates by covalent linkage of HRP and anti-TGF onto V-Phe-SWCNT hybrids. Biotinylated anti-TGF antibodies were immobilized onto 4-carboxyphenyl-functionalized SPCEs modified with streptavidin and a sandwich type immunoassay was implemented for TGF-β1 with signal amplification using V-Phe-SWCNT(-HRP)-anti-TGF conjugates as carrier tags. The analytical characteristics exhibited by the as prepared immunosensor (range of linearity between 2.5 and 1000pgmL−1 TGF-β1; detection limit of 0.95pgmL−1) improve notably those reported with other previous immunosensors or ELISA kits. A great selectivity against other proteins was also found. The prepared immunosensor was validated by determining TGF-β1 in real saliva samples. Minimal sample treatment was required and the obtained results were in excellent agreement with those obtained by using a commercial ELISA kit.
•Synthesis of viologen-SWCNT hybrids by aryl-diazonium chemistry.•Preparation of TGF-β1 immunosensor by grafting with 4-carboxyphenyl onto screen-printed carbon electrodes.•Signal amplification using V-Phe-SWCNT(-HRP)-anti-TGF as carrier nanotags.•Application to real saliva samples.