Scaling of transverse nuclear magnetic relaxation due to magnetic nanoparticle aggregation
The aggregation of superparamagnetic iron oxide (SPIO) nanoparticles decreases the transverse nuclear magnetic resonance (NMR) relaxation time T[CP over 2] of adjacent water molecules measured by a Carr-Purcell-Meiboom-Gill (CPMG) pulse-echo sequence. This effect is commonly used to measure the conc...
| Main Authors: | , , , , , |
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| Other Authors: | |
| Format: | Article |
| Language: | en_US |
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Elsevier
2015
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| Online Access: | http://hdl.handle.net/1721.1/99405 https://orcid.org/0000-0003-2379-6139 |
| _version_ | 1811069507741941760 |
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| author | Brown, Keith A. Vassiliou, Christophoros C. Issadore, David Berezovsky, Jesse Cima, Michael J. Westervelt, R.M. |
| author2 | Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science |
| author_facet | Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science Brown, Keith A. Vassiliou, Christophoros C. Issadore, David Berezovsky, Jesse Cima, Michael J. Westervelt, R.M. |
| author_sort | Brown, Keith A. |
| collection | MIT |
| description | The aggregation of superparamagnetic iron oxide (SPIO) nanoparticles decreases the transverse nuclear magnetic resonance (NMR) relaxation time T[CP over 2] of adjacent water molecules measured by a Carr-Purcell-Meiboom-Gill (CPMG) pulse-echo sequence. This effect is commonly used to measure the concentrations of a variety of small molecules. We perform extensive Monte Carlo simulations of water diffusing around SPIO nanoparticle aggregates to determine the relationship between T[CP over 2] and details of the aggregate. We find that in the motional averaging regime T[CP over 2] scales as a power law with the number N of nanoparticles in an aggregate. The specific scaling is dependent on the fractal dimension d of the aggregates. We find T[CP over 2] ∝ Ν[superscript −0.44] for aggregates with d = 2.2, a value typical of diffusion limited aggregation. We also find that in two-nanoparticle systems, T[CP over 2] is strongly dependent on the orientation of the two nanoparticles relative to the external magnetic field, which implies that it may be possible to sense the orientation of a two-nanoparticle aggregate. To optimize the sensitivity of SPIO nanoparticle sensors, we propose that it is best to have aggregates with few nanoparticles, close together, measured with long pulse-echo times. |
| first_indexed | 2024-09-23T08:11:33Z |
| format | Article |
| id | mit-1721.1/99405 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T08:11:33Z |
| publishDate | 2015 |
| publisher | Elsevier |
| record_format | dspace |
| spelling | mit-1721.1/994052022-09-23T11:29:26Z Scaling of transverse nuclear magnetic relaxation due to magnetic nanoparticle aggregation Brown, Keith A. Vassiliou, Christophoros C. Issadore, David Berezovsky, Jesse Cima, Michael J. Westervelt, R.M. Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology. Department of Materials Science and Engineering Koch Institute for Integrative Cancer Research at MIT Vassiliou, Christophoros C. Cima, Michael J. The aggregation of superparamagnetic iron oxide (SPIO) nanoparticles decreases the transverse nuclear magnetic resonance (NMR) relaxation time T[CP over 2] of adjacent water molecules measured by a Carr-Purcell-Meiboom-Gill (CPMG) pulse-echo sequence. This effect is commonly used to measure the concentrations of a variety of small molecules. We perform extensive Monte Carlo simulations of water diffusing around SPIO nanoparticle aggregates to determine the relationship between T[CP over 2] and details of the aggregate. We find that in the motional averaging regime T[CP over 2] scales as a power law with the number N of nanoparticles in an aggregate. The specific scaling is dependent on the fractal dimension d of the aggregates. We find T[CP over 2] ∝ Ν[superscript −0.44] for aggregates with d = 2.2, a value typical of diffusion limited aggregation. We also find that in two-nanoparticle systems, T[CP over 2] is strongly dependent on the orientation of the two nanoparticles relative to the external magnetic field, which implies that it may be possible to sense the orientation of a two-nanoparticle aggregate. To optimize the sensitivity of SPIO nanoparticle sensors, we propose that it is best to have aggregates with few nanoparticles, close together, measured with long pulse-echo times. American Society for Engineering Education. National Defense Science and Engineering Graduate Fellowship MIT-Harvard Center of Cancer Nanotechnology Excellence National Science Foundation (U.S.). Division of Materials Research (Award 0746264) 2015-10-22T12:46:27Z 2015-10-22T12:46:27Z 2010-05 2010-05 Article http://purl.org/eprint/type/JournalArticle 03048853 http://hdl.handle.net/1721.1/99405 Brown, Keith A., Christophoros C. Vassiliou, David Issadore, Jesse Berezovsky, Michael J. Cima, and R.M. Westervelt. “Scaling of Transverse Nuclear Magnetic Relaxation Due to Magnetic Nanoparticle Aggregation.” Journal of Magnetism and Magnetic Materials 322, no. 20 (October 2010): 3122–3126. https://orcid.org/0000-0003-2379-6139 en_US http://dx.doi.org/10.1016/j.jmmm.2010.05.044 Journal of Magnetism and Magnetic Materials Creative Commons Attribution-Noncommercial-NoDerivatives http://creativecommons.org/licenses/by-nc-nd/4.0/ application/pdf Elsevier Arxiv |
| spellingShingle | Brown, Keith A. Vassiliou, Christophoros C. Issadore, David Berezovsky, Jesse Cima, Michael J. Westervelt, R.M. Scaling of transverse nuclear magnetic relaxation due to magnetic nanoparticle aggregation |
| title | Scaling of transverse nuclear magnetic relaxation due to magnetic nanoparticle aggregation |
| title_full | Scaling of transverse nuclear magnetic relaxation due to magnetic nanoparticle aggregation |
| title_fullStr | Scaling of transverse nuclear magnetic relaxation due to magnetic nanoparticle aggregation |
| title_full_unstemmed | Scaling of transverse nuclear magnetic relaxation due to magnetic nanoparticle aggregation |
| title_short | Scaling of transverse nuclear magnetic relaxation due to magnetic nanoparticle aggregation |
| title_sort | scaling of transverse nuclear magnetic relaxation due to magnetic nanoparticle aggregation |
| url | http://hdl.handle.net/1721.1/99405 https://orcid.org/0000-0003-2379-6139 |
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