UC Davis researchers have created a new type of nanoparticle, magnetic and luminescent, that could be used in tests for environmental pollution or contamination of food products, and for medical diagnostics.

The particles, about 100 to 200 nanometers in size and inexpensive to make, comprise 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.

The nanoparticles can be manipulated with magnets and detected by fluorescence. 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 and senior author on a paper describing the work.

The particles can be coated with short pieces of DNA and used for genetic analysis. Other uses could include testing for bioterrorism agents such as ricin or botulinum toxin in food, and for genetic tests in cancer medicine.

Other authors on the paper are research specialist Dosi Dosev, Department of Mechanical and Aeronautical Engineering; postdoctoral researcher Mikaela Nichkova, research associate Shirley Gee and Professor Bruce Hammock, all of the Department of Entomology; and Kai Liu, associate professor of physics, and Randy Dumas, physics graduate student.

The paper can be read now in the online version of the journal Nanotechnology and is set to appear in the print edition dated Feb. 7.