Magnetic Manipulation of Blood Conductivity with Superparamagnetic Iron Oxide-Loaded Erythrocytes

Gavin R. Philips, Bernhard Gleich, Genaro A. Paredes-Juarez, Antonella Antonelli, Mauro Magnani, Jeff W.M. Bulte

Research output: Contribution to journalArticlepeer-review


The active and passive electrophysiological properties of blood and tissue have been utilized in a vast array of clinical techniques to noninvasively characterize anatomy and physiology and to diagnose a wide variety of pathologies. However, the accuracy and spatial resolution of such techniques are limited by several factors, including an ill-posed inverse problem, which determines biological parameters and signal sources from surface potentials. Here, we propose a method to noninvasively modulate tissue conductivity by aligning superparamagnetic iron oxide-loaded erythrocytes with an oscillating magnetic field. A prototype device is presented, which incorporates a three-dimensional set of Helmholtz coil pairs and fluid-channel-embedded electrode arrays. Alignment of loaded cells (∼11 mM iron) within a field of 12 mT is demonstrated, and this directed reorientation is shown to alter the conductivity of blood by ∼5 and ∼0.5% for stationary and flowing blood, respectively, within fields as weak as 6-12 mT. Focal modulation of conductivity could drastically improve numerous bioimpedance-based detection modalities.

Original languageEnglish (US)
Pages (from-to)11194-11201
Number of pages8
JournalACS Applied Materials and Interfaces
Issue number12
StatePublished - Mar 27 2019


  • bioimpedance
  • blood conductivity
  • electrophysiology
  • iron oxide nanoparticles
  • red blood cells

ASJC Scopus subject areas

  • Materials Science(all)


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