Liver cancer immunoassay with magnetic nanoparticles and MgO-based magnetic tunnel junction sensors

Lei, Z. Q.; Li, L.; Li, G. J.; Leung, C. W.; Shi, J.; Wong, C. M.; Lo, K. C.; Chan, W. K.; Mak, C. S. K.; Chan, S. B.; Chan, N. M. M.; Leung, C. H.; Lai, P. T.; Pong, P. W. T.

doi:10.1063/1.3676212

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Research Article| Magnetism and Magnetic Materials| March 05 2012

Liver cancer immunoassay with magnetic nanoparticles and MgO-based magnetic tunnel junction sensors

Z. Q. Lei;

Z. Q. Lei

1

Department of Electrical and Electronic Engineering, The University of Hong Kong

,

Hong Kong

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L. Li;

L. Li

1

Department of Electrical and Electronic Engineering, The University of Hong Kong

,

Hong Kong

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G. J. Li;

G. J. Li

1

Department of Electrical and Electronic Engineering, The University of Hong Kong

,

Hong Kong

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C. W. Leung;

C. W. Leung

2

Department of Applied Physics, The Hong Kong Polytechnic University

,

Hong Kong

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J. Shi;

J. Shi

3

Department of Physics, Hong Kong Baptist University

,

Hong Kong

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C. M. Wong;

C. M. Wong

4

Department of Pathology, The University of Hong Kong

,

Hong Kong

5

State Key Laboratory for Liver Research, The University of Hong Kong

,

Hong Kong

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K. C. Lo;

K. C. Lo

6

Department of Chemistry, The University of Hong Kong

,

Hong Kong

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W. K. Chan;

W. K. Chan

6

Department of Chemistry, The University of Hong Kong

,

Hong Kong

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C. S. K. Mak;

C. S. K. Mak

6

Department of Chemistry, The University of Hong Kong

,

Hong Kong

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S. B. Chan;

S. B. Chan

1

Department of Electrical and Electronic Engineering, The University of Hong Kong

,

Hong Kong

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N. M. M. Chan;

N. M. M. Chan

7

Department of Surgery, University of Cambridge

,

United Kingdom

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C. H. Leung;

C. H. Leung

1

Department of Electrical and Electronic Engineering, The University of Hong Kong

,

Hong Kong

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P. T. Lai;

P. T. Lai

1

Department of Electrical and Electronic Engineering, The University of Hong Kong

,

Hong Kong

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P. W. T. Pong

P. W. T. Pong ^a)

1

Department of Electrical and Electronic Engineering, The University of Hong Kong

,

Hong Kong

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Author & Article Information

Z. Q. Lei ¹

,

L. Li ¹

,

G. J. Li ¹

,

C. W. Leung ²

,

J. Shi ³

,

C. M. Wong ^4,5

,

K. C. Lo ⁶

,

W. K. Chan ⁶

,

C. S. K. Mak ⁶

,

S. B. Chan ¹

,

N. M. M. Chan ⁷

,

C. H. Leung ¹

,

P. T. Lai ¹

,

P. W. T. Pong ^1,a)

1

Department of Electrical and Electronic Engineering, The University of Hong Kong

,

Hong Kong

2

Department of Applied Physics, The Hong Kong Polytechnic University

,

Hong Kong

3

Department of Physics, Hong Kong Baptist University

,

Hong Kong

4

Department of Pathology, The University of Hong Kong

,

Hong Kong

5

State Key Laboratory for Liver Research, The University of Hong Kong

,

Hong Kong

6

Department of Chemistry, The University of Hong Kong

,

Hong Kong

7

Department of Surgery, University of Cambridge

,

United Kingdom

^a)

Electronic mail: [email protected].

J. Appl. Phys. 111, 07E505 (2012)

https://doi.org/10.1063/1.3676212

We have demonstrated the detection of alpha-fetoprotein (AFP) labeled with magnetic nanoparticles (MNPs) using MgO-based magnetic tunnel junction (MTJ) sensors. AFP is an important hepatic tumor biomarker and the detection of AFP has significant applications for clinical diagnostics and immunoassay for early-stage liver cancer indications. In this work, MgO-based MTJ sensors and 20-nm iron-oxide magnetic nanoparticles (MNPs) were used for detecting AFP antigens by a sandwich-assay configuration. The MTJ sensors with a sensing area of 4 × 2 μm² possess tunneling magnetoresistance (TMR) of 122% and sensitivity of 0.95%/Oe at room temperature. The target AFP antigens of three concentrations were successfully detected, and the experimental data indicate that the resistance variations of the MTJ sensor increased with the AFP concentration ratios proportionally. These results demonstrate that MgO-based MTJ sensors together with MNPs are a promising biosensing platform for liver cancer immunoassay.