Invited Paper MI+BI-ThA8
Magnetic Nanoparticles in Biomedicine: Recent Developments in Imaging, Diagnostics and Therapy

Thursday, October 25, 2018, 4:40 pm, Room 203A

The Néel relaxation of magnetic nanoparticles (MNP), subject to alternating magnetic fields in solution, depends exponentially on their core diameter while the complementary Brownian relaxation mechanism depends critically on their hydrodynamic volume [1]. Recent developments [2] in the synthesis of highly monodisperse and phase-pure magnetite nanoparticles allows for reproducible control of the former in biological environments, enabling novel imaging [3,4] and spectroscopic modalities, under ac excitations such as magnetic particle imaging/spectroscopy (MPI/MPS) with superior resolution and sensitivity [5]. [8] .

Magnetic Particle Imaging (MPI) is an emerging, tracer-based, whole-body medical imaging technology with high image contrast (no tissue background) and sensitivity (~250 nm Fe) to an optimized tracer consisting of an iron-oxide nanoparticle core and a biofunctionalized shell. MPI is linearly quantitative with tracer concentration and has zero tissue depth attenuation. MPI is also safe, uses no ionizing radiation and clinically approved tracers. MPI is also the first biomedical imaging technique that truly depends on nanoscale materials properties; in particular, their response to alternating magnetic fields in a true biological environment needs to be optimized.

In this talk, I will introduce the underlying physics of MPI, the alternative approaches to image reconstruction, and describe recent results in the development of our highly optimized and functionalized nanoparticle tracers for MPI. I will then present state-of-the-art imaging results of preclinical in vivo MPI experiments of cardiovascular (blood-pool) imaging [6], stroke [7], GI bleeding [8], and cancer [9] using rodent models. I will also discuss a related diagnostic method using magnetic relaxation and illustrate its use for detecting specific protease cancer markers in solution [10]. If time permits, I will introduce therapeutic applications of magnetic nanoparticles [11].

[1] Kannan M. Krishnan, IEEE Trans. Mag. 46, 2523 (2010)

[2] S. J. Kemp, R.M. Ferguson, A. P. Khandhar and Kannan M. Krishnan, RSC Advances, 6, 77452 (2016).

[3] B. Gleich & J. Weizenecker, Nature 435, 1214 (2005).

[4] R.M. Ferguson, et al, IEEE Trans. Med. Imag. 34, 1077 (2015)

[5] M. Graeser et al, Scientific Reports, 7, 6872 (2017)

[6] A. Khandhar et al, Nanoscale 9,1299 (2017)

[7] P. Ludewig et al, ACS Nano 11, 10480 (2017)

[8] E. Y. Yu et al, ACS Nano 11, 12067 (2017

[9] H. Arami et al, Nanoscale 9, 18723 (2017)

[10] S. Gandhi, H. Arami and Kannan M. Krishnan, Nanoletters 16, 3668 (2016)

[11] This work was supported by NIH grants 1RO1EB013689-01, 1R41EB013520-01, 2R42-EB013520-02A1 and 1R24-MH109085 .