Sensitive and high-fidelity electrochemical immunoassay using carbon nanotubes coated with enzymes and magnetic nanoparticles

Yunxian Piao, Zongwen Jin, Dohoon Lee, Hye Jin Lee, Hyon Bin Na, Taeghwan Hyeon, Min-Kyu Oh, Jungbae Kim, Hak Sung Kim

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

We demonstrate a highly sensitive electrochemical immunosensor based on the combined use of substrate recycling and carbon nanotubes (CNTs) coated with tyrosinase (TYR) and magnetic nanoparticles (MNP). Both TYR and MNP were immobilized on the surface of CNTs by covalent attachment, followed by additional cross-linking via glutaraldehyde treatment to construct multi-layered cross-linked TYR-MNP aggregates (M-EC-CNT). Magnetically capturable, highly active and stable M-EC-CNT were further conjugated with primary antibody against a target analyte of hIgG, and used for a sandwich-type immunoassay with a secondary antibody conjugated with alkaline phosphatase (ALP). In the presence of a target analyte, a sensing assembly of M-EC-CNT and ALP-conjugated antibody was attracted onto a gold electrode using a magnet. On an electrode, ALP-catalyzed hydrolysis of phenyl phosphate generated phenol, and successive TYR-catalyzed oxidation of phenol produced electrochemically measurable o-quinone that was converted to catechol in a scheme of substrate recycling. Combination of highly active M-EC-CNT and substrate recycling for the detection of hIgG resulted in a sensitivity of 27.6nAng-1mL-1 and a detection limit of 0.19ngmL-1 (1.2pM), respectively, representing better performance than any other electrochemical immunosensors relying on the substrate recycling with the TYR-ALP combination. The present immunosensing system also displayed a long-term stability by showing a negligible loss of electrochemical detection signal even after reagents were stored in an aqueous buffer at 4°C for more than 6 months.

Original languageEnglish
Pages (from-to)3192-3199
Number of pages8
JournalBiosensors and Bioelectronics
Volume26
Issue number7
DOIs
Publication statusPublished - 2011 Mar 15

Fingerprint

Carbon Nanotubes
Immunoassay
Monophenol Monooxygenase
Nanoparticles
Carbon nanotubes
Enzymes
Phosphatases
Recycling
Alkaline Phosphatase
Antibodies
Immunosensors
Substrates
Phenol
Phenols
Electrodes
Magnets
Signal detection
Glutaral
Gold
Limit of Detection

Keywords

  • Carbon nanotube
  • Electrochemical immunoassay
  • Enzyme coating
  • Substrate recycling
  • Tyrosinase

ASJC Scopus subject areas

  • Biophysics
  • Biomedical Engineering
  • Biotechnology
  • Electrochemistry

Cite this

Sensitive and high-fidelity electrochemical immunoassay using carbon nanotubes coated with enzymes and magnetic nanoparticles. / Piao, Yunxian; Jin, Zongwen; Lee, Dohoon; Lee, Hye Jin; Na, Hyon Bin; Hyeon, Taeghwan; Oh, Min-Kyu; Kim, Jungbae; Kim, Hak Sung.

In: Biosensors and Bioelectronics, Vol. 26, No. 7, 15.03.2011, p. 3192-3199.

Research output: Contribution to journalArticle

Piao, Yunxian ; Jin, Zongwen ; Lee, Dohoon ; Lee, Hye Jin ; Na, Hyon Bin ; Hyeon, Taeghwan ; Oh, Min-Kyu ; Kim, Jungbae ; Kim, Hak Sung. / Sensitive and high-fidelity electrochemical immunoassay using carbon nanotubes coated with enzymes and magnetic nanoparticles. In: Biosensors and Bioelectronics. 2011 ; Vol. 26, No. 7. pp. 3192-3199.
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