Facultat de Física

Departament de Física de la Matèria Condensada

Magnetism in Biomedicine: Translating Science to Clinical Applications

Prof. Kannan M. Krishnan

Universitat de Washington (USA).

Recent developments in synthesis and optimization of magnetite nanoparticles. with negligible toxicity and favorable biodistribution, allows for reproducible control of their complex magnetic relaxation behavior even in “extreme” biological environments. This has enabled us to address two of the principal challenges in biomedicine, i.e. detecting disease at the earliest possible time prior to its ability to cause damage (imaging and diagnostics) and delivering treatment at the right place, at the right time whilst minimizing exposure (targeted therapy with a triggered release). Central to this work is the size-dependent magnetic properties of nanoparticles and specifically tailoring their Néel and Brownian relaxation dynamics in vivo to any specific applied frequency. Such work also requires coordinated efforts in synthesis of highly-monodisperse and phase-pure magnetite cores, biochemical surface functionalization, biodistribution and pharmacokinetic studies, advanced characterization, and stochastic modeling of magnetization response. Currently, our work is focused on Magnetic Particle Imaging (MPI), a tracer-based, whole-body imaging technology with high contrast (no tissue background) and nanogram sensitivity. MPI is linearly quantitative with tracer concentration and has zero tissue depth attenuation; it is also safe and uses no ionizing radiation. In this talk, I will introduce the underlying physics of MPI, and describe results in the development of 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, stroke, GI bleeding, and cancer, all using rodent models. If time permits, I will also discuss a related diagnostic method using magnetic relaxation and illustrate its use for detecting specific protease cancer markers in solution. Throughout this talk I will highlight conceptual ideas that help bridge the gap for physical scientists interested in working on translational problems in biomedicine.