FerroFluid Challenge

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FerroFluid Extensions



FerroFluid is a substance which is, in all likelihood, like nothing you've ever seen before. The term is used to refer to a classification of fluid (usually water or oil) which has had large quantities of iron oxide nanoparticles (~10nm diameter) suspended within it. The combination gives the substance magnetic properties. These liquids are referred to as superparamagnetic, meaning that they only display magnetic properties when exposed to an existing magnetic field, and do not retain any ordering of magnetic domains after the field has been removed. When exposed to a field, ferrofluids respond by aggregating along the magnetic field lines. The combination of the magnetic field and the effects of gravity serve to create a characteristic 'hedgehog' pattern in the exposed fluid. Many examples of this effect can be easily located though search engines.

Current Uses

Ferrofluid appears in a number of current technologies, but is usually incorporated in such a way that the user remains unaware of its presence. The magnetic properties of ferrofluids are utilized in most modern hard drives to create a seal around the drive which prevents dust and other particles from entering. Sealing techniques are also used occasionally in high quality DC motors of both brushed and brushless variety. The fluids are also used for their ability to damp oscillations in certain magnetic systems such as stepper motors. Another unique property of ferrofluid is its response to applied electric fields, which can change the liquid's viscosity. This property has been recently been exploited to create shock absorbers for cars. There are also several biomedical applications for ferrofluid including better medical imaging, healing cancer tumors, and focused drug delivery.

Potential for Drug Delivery

Another speculative usage for ferrofluid is as a vessel for delivering drugs to specific locations inside the human body. Preliminary work done has suggested that the fluids can be used to encapsulate small quantities of medications and then be coated in proteins to prevent the body's defense systems from attacking the particles. The particles could then be guided to a specific site by an externally applied magnetic field. Such a delivery system would be particularly useful for cancer treatment, as many medicines used in chemotherapy are poisonous to healthy, as well as cancerous tissue. Delivery to the specific site of the cancer would increase the drugs effectiveness and lower its side effects.


The ferrofluid challenge is pending and should be available 4th quarter of 2007.

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