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ST518 - Magnetic Relaxometry as Applied to Sensitive Cancer Detection and Localization

Magnetic Relaxometry as Applied to Sensitive Cancer Detection and

Leyma P. De Haro1, Todor Karaulanov1, Erika C. Vreeland1, Bill Anderson1,
Helen J. Hathaway2, Dale L. Huber3, Andrei N. Matlashov4, Christopher P. Nettles1, Andrew D. Price1, Todd C. Monson5, and Edward R. Flynn1

1Senior Scientific, LLC, 800 Bradbury SE, Albuquerque, NM 87106, USA
2Department of Cell Biology and Physiology, University of New Mexico School of Medicine, Albuquerque, NM, USA
3Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, NM, USA
4Los Alamos National Laboratory, Group of Applied Modern Physics, Los Alamos, NM, USA
5Sandia National Laboratories. Nanoscale Sciences Department, Albuquerque, NM, USA

E-mail: [email protected]

Abstract — 
Here we describe superparamagnetic relaxometry (SPMR), a technology that utilizes highly sensitive magnetic sensors and superparamagnetic nanoparticles for cancer detection. Using SPMR, we sensitively and specifically detect nanoparticles conjugated to biomarkers for various types of cancer. SPMR offers high contrast in vivo, as there is no superparamagnetic background, and bones and tissue are transparent to the magnetic fields.

Methods: In SPMR measurements, a brief magnetizing pulse is used to align superparamagnetic nanoparticles of a discrete size. Following the pulse, an array of superconducting quantum interference detectors (SQUID) sensors detect the decaying magnetization field. NP size is chosen so that, when bound, the induced field decays in seconds. They are functionalized with specific biomarkers and incubated with cancer cells in vitro to determine specificity and cell binding. For in vivo experiments, functionalized NPs are injected into mice with xenograft tumors, and field maps are generated to localize tumor sites.

Results: Superparamagnetic NPs developed here have small size dispersion. Cell incubation studies measure specificity for different cell lines and antibodies with very high contrast. In vivo animal measurements verify SPMR localization of tumors. Our results indicate that SPMR possesses sensitivity more than 2 orders of magnitude better
than previously reported.

Keywords (Index Terms) — Cancer; magnetic relaxometry; nanoparticles; SQUID.

Reference No. STP518; Category 4. 
Reprinted with permission from Leyma P. De Haro et al., Biomed. Eng.-Biomed. Tech. 60(5), 445–455 (2015) DOI 10.1515/bmt-2015-0053.