Prof. Markus Zahn

Professor of Electrical Engineering, Emeritus
Director, 6-A Internship Program

Primary DLC

Department of Electrical Engineering and Computer Science

MIT Room: 10-174

Areas of Interest and Expertise

Electro-Optical Field and Charge Mapping Measurements
High-Voltage Charge Transport and Breakdown Phenomena in Dielectrics
Flow Electrification Phenomena in Electric Power Apparatus
Development of Capacitive and Inductive Sensors for Measuring Profiles of Dielectric, Conduction, and Magnetic Properties of Media
Electrohydrodynamic, Electrokinetic, and Ferrohydrodynamic Interactions with Charged, Polarizable and Magnetic Fluids

Research Summary

Professor Zahn's research interests are in MEMS/NEMS sensor and actuator devices using dielectric and magnetic nanoparticles; micro/nano fluidics; electrophoresis, dielectrophoresis and magnetophoresis. He wants to extend these interests to applications for nanobiosensors, targeted drug-delivery vectors, magnetocytolysis of cancerous tumors, separations and cell sorting, magnetic resonance imaging, and in immunoassays.

Related research in the the MIT High Voltage Research Laboratory (HVRL) is focused on electrohydrodynamic and ferrohydrodynamic interactions with media.

The Zahn laboratory applies micro/nano fluidics, dielectrometry and magnetometry measurements, electromechanics, and electro-optical sensing to practical problems in electrohydrodynamics and ferrohydrodynamics, non-destructive testing and evaluation, and development of sensors and actuators. Current research focuses on developing and studying microelectromechanical (MEMS) and nanoelectromechanical (NEMS) sensor and actuator devices based on dielectric and magnetic nanoparticles, with a special interest in magnetic liquids (ferrofluids) and for enhanced magnetic resonance imaging by controlling the magnetic susceptibility tensor by causing the magnetic nanoparticles to spin in a rotating magnetic field. In past collaborations, this group investigated the health effects of electromagnetic fields. They now have joined CSBi specifically to seek interdisciplinary collaborations in which they can apply their expertise in electromagnetism, colloidal chemistry and fluid mechanics to current biomedical problems.

One of this group's research specialties is the use of magnetic liquids, which are suspensions of magnetic nanoparticles that can be functionalized for a variety of applications. Magnetic fluids consist of three components: a carrier liquid such as water, which provides fluid mechanics; the ~10 nm diameter magnetic iron-containing particles themselves; and a surfactant that prevents particle agglomeration and helps disperse the particles in a uniform suspension. The particles are small and sufficiently dispersed that they can circulate through the bloodstream. Various surfactants also have colloidal properties that confer specific functionalities to the particles for a variety of potential biomedical applications such as:

(*) Selective adsorption of drugs and proteins for targeted delivery in vivo.
(* ) Specific adsorption of toxins for selective removal from the body.
(*) Sequestration at tumor sites in the body, where they can be heated in situ by microwave or magnetic methods so that they selectively kill tumor cells (the process of selective hyperthermic ablation or magnetocytolysis).
(*) Other applications such as magnetic-based immunoassays, nanobiosensors, separations and cell sorting, and enhanced magnetic resonance imaging.

One focus of the Zahn lab is studying how magnetic nanoparticles react to DC, alternating, and rotating magnetic fields by organizing into magnetically controllable, self-assembling magnetic fluid patterns and structures. A videotape of some of these self-assembling sequences was a winner in the 2003 Gallery of Fluid Motion of the American Physical Society's Division of Fluid Dynamics.

Recent Work