Luminescent Magnetic Nanoparticles Used for Diagnostic Tests

A new type of nanoparticle has been created that could be used in tests for medical diagnostics, environmental pollution, or contamination of food products.

The particles, about 100 to 200 nm in size, are luminescent, magnetic, and inexpensive to make, and can be tagged with antibodies. They are made up of a magnetic core of iron oxide or iron/neodymium/cobalt oxide coated in a shell of europium and gadolinium oxide. When stimulated with a laser, europium emits red light at a very specific wavelength.

The nanoparticles can be manipulated with magnets and detected by fluorescence. They could also be labeled with other fluorescent labels in different colors, or used as part of an assay with other fluorescent labels. The built-in europium luminescence acts as an internal standard, making it easier to carry out accurate quantitative assays, said Ian Kennedy, professor of mechanical and aeronautical engineering at the University of California Davis (Davis, CA, USA), and senior author of a paper describing the work. The paper is published in the online journal Nanotechnology and will appear in the February 7, 2007, print issue of the journal.

The particles can also be coated with short pieces of DNA and used for genetic analysis. The team is exploring uses including testing for bioterrorism agents such as ricin or botulinum toxin in food and for genetic tests in cancer medicine.

The nanoparticles were made by spray pyrolysis, which involves mixing the raw material in a solvent and spraying it through a flame. The method is much cheaper than the techniques previously used for making similar particles, and can readily be scaled up to industrial production. It is already used in the chemical industry to make products such as fumed silica and carbon black.

The researchers are establishing a company, Synthia LLC, to develop the technology further.



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