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Sensors 2014, 14(11), 21409-21417;

Using Bio-Functionalized Magnetic Nanoparticles and Dynamic Nuclear Magnetic Resonance to Characterize the Time-Dependent Spin-Spin Relaxation Time for Sensitive Bio-Detection

Institute of Electro-Optical Science and Technology, National Taiwan Normal University, Taipei 116, Taiwan
Department of Electro-Optical Engineering, Kun Shan University, Tainan 710, Taiwan
Department of Physics, National Chung Hsing University, Taichung 402, Taiwan
Graduate Institute of Applied Physics and Department of Physics, National Taiwan University, Taipei 106, Taiwan
Authors to whom correspondence should be addressed.
Received: 12 September 2014 / Revised: 24 October 2014 / Accepted: 29 October 2014 / Published: 12 November 2014
(This article belongs to the Special Issue Nanoparticle-Based Biosensors)
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In this work, we report the use of bio-functionalized magnetic nanoparticles (BMNs) and dynamic magnetic resonance (DMR) to characterize the time-dependent spin-spin relaxation time for sensitive bio-detection. The biomarkers are the human C-reactive protein (CRP) while the BMNs are the anti-CRP bound onto dextran-coated Fe3O4 particles labeled as Fe3O4-antiCRP. It was found the time-dependent spin-spin relaxation time, T2, of protons decreases as time evolves. Additionally, the ΔT2 of of protons in BMNs increases as the concentration of CRP increases. We attribute these to the formation of the magnetic clusters that deteriorate the field homogeneity of nearby protons. A sensitivity better than 0.1 μg/mL for assaying CRP is achieved, which is much higher than that required by the clinical criteria (0.5 mg/dL). The present MR-detection platform shows promise for further use in detecting tumors, viruses, and proteins. View Full-Text
Keywords: NMR; spin-spin relaxation time; CRP NMR; spin-spin relaxation time; CRP

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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

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Liao, S.-H.; Chen, K.-L.; Wang, C.-M.; Chieh, J.-J.; Horng, H.-E.; Wang, L.-M.; Wu, C.H.; Yang, H.-C. Using Bio-Functionalized Magnetic Nanoparticles and Dynamic Nuclear Magnetic Resonance to Characterize the Time-Dependent Spin-Spin Relaxation Time for Sensitive Bio-Detection. Sensors 2014, 14, 21409-21417.

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