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Magnetic Field-assisted Fabrication and Manipulation of Non-Spherical Polymer Particles in Ferrofluid-based Droplet Microfluidics


Project TitleMagnetic Field-assisted Fabrication and Manipulation of Non-Spherical Polymer Particles in Ferrofluid-based Droplet Microfluidics
Track Code1675
Short Description

The invention is a method-device combination for the reproducible fabrication of microparticles for drug-delivery, bioimaging, biometrics and special tagging, among other buses. Non-spherical particles are beneficial for drug delivery, bioimaging and biometrics due to their large surface area. The dominant shape of polymer particles has been spherical because of the difficulty of manufacturing large quantities of monodispersed particles with tunable shapes and sizes. This process controls the shape and assembly of polymer droplets within a flow-focusing droplet microfluidic device to form non-spherical particles and chains. The method relies on water-based magnetic liquid (ferrofluid) as a continuous phase to (1) induce droplet formation (2) controllably change the shape of droplets, and (3) assemble droplets into chains. These ferrofluids induce magnetic dipole movement within the droplets, making it possible for the droplets to deform to non-spherical shapes and assemble into chains of tunable lengths.


Placing the polymers in a ferrofluid allows for manipulation of their shape, as well as creating tunable length chains. When an external magnetic field gradient is applied, the non-magnetic polymer droplets inside ferrofluids experience both magnetic and hydrodynamic drag forces. This force can be used to stretch the spherical shape of droplets into ellipsoids of different sizes. Other shapes are also possible with different designs of magnetic field patterns. The ferrofluids also promote dipole-dipole interactions, leading to the assembly of linear chains with tunable lengths oriented along the magnetic field direction. In non-optimized, lab-scale process and using a single device, non-spherical droplets or chains can be produced at a rate of 1000 per second.  The method is scalable.

References and Intellectual Property


  • US Patent 8,721,936

  • Zhu, T., Cheng, R., Sheppard, G., Locklin, J., Mao, L., “Magnetic-Field-Assisted Fabrication and Manipulation of Nonspherical Polymer Particles in Ferrofluid-Based Droplet Microfluidics”, Langmuir, 2015

Tagspolymer, particles, ferrofluid, drug delivery, therapeutics, magnetic
Posted DateNov 14, 2017 3:10 PM


Cheryl Junker