Nanoparticles and the Power of Two

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A quantum dot (red) encapsulated in a gold shell, combines two useful nanoparticles in one package. The total structure measures less than 20 nm across. Image: UW

A team of researchers at the University of Washington (Seattle) has discovered that encapsulating a quantum dot in a gold shell produces a "multipurpose nanotechnology tool for medical imaging and therapy."Previous research attempts have combined a quantum dot and gold nanoparticle on a surface. But combining the two components had proved difficult because their electric fields tend to interfere with one another, thereby altering each component's behavior.To combine the semiconductor and metal nanoparticles, the UW researchers employed a protein-based manufacturing process. Proteins surround the quantum dot and provide a 3-nm buffer between the quantum dot core and the thin gold shell to ensure that the materials' optical and electrical fields do not interfere with one another. As a result, the two-in-one nanoparticle lends itself to fluorescent imaging, as well as scattering-based imaging and heat therapy, according to the team.