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

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

Research output: Journal article publicationJournal articleAcademic researchpeer-review

20 Citations (Scopus)


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 μm2possess tunneling magnetoresistance (TMR) of 122 and sensitivity of0.95/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.
Original languageEnglish
Article number07E505
JournalJournal of Applied Physics
Issue number7
Publication statusPublished - 1 Apr 2012

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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