Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Integrated microfluidic isolation platform for magnetic particle manipulation in biological systems



Elizabeth Mirowski, John M. Moreland, Stephen E. Russek, Michael J. Donahue


We have developed a micromachined fluid-cell platform that consists of patterned magnetic thin-film elements supported on a thin silicon-nitride membrane. In the presence of an external magnetic field, the field gradients near the magnetic elements are sufficiently large to trap magnetic particles that are separated from the patterned films by a 200 nm thick nitride membrane. The two main applications of this fluid-cell platform are to provide a means to control and position magnetic microparticles, based on their size and magnetic susceptibility. We determine the characteristic trapping forces of each trap in the array by measuring the Brownian motion of the microparticle as a function of applied external field. Typical force constants and forces on the superparamagnetic particles are 4.8 x 10-4 plus or minus} 0.7 x 10-4 N/m and 97 plus or minus} 15 pN respectively.
Applied Physics Letters


biology, force, magnetic particles, magnetic tweezers, manipulation, microfluidic


Mirowski, E. , Moreland, J. , Russek, S. and Donahue, M. (2004), Integrated microfluidic isolation platform for magnetic particle manipulation in biological systems, Applied Physics Letters, [online], (Accessed June 19, 2024)


If you have any questions about this publication or are having problems accessing it, please contact

Created March 7, 2004, Updated October 12, 2021