Tushar Sathe holds a vial of dual-function beads embedded with iron oxide and 600 nanometer emission quantum dots, while Shuming Nie looks on. The other vials contain beads embedded with quantum dots that emit light at other wavelengths. photo by Gary Meek

Analyzing human blood for a very low virus concentration or a sample of water for a bioterrorism agent has always been a time-consuming and difficult process. Researchers at the Georgia Institute of Technology and Emory University have developed an easier and faster method to detect these types of target molecules in liquid samples using highly porous, micron-sized, silica beads.

The researchers developed a technique to simultaneously or sequentially add optical and magnetic nanoparticles into the beads. Adding magnetic nanoparticles allows the use of a magnetic field to attract and easily remove the beads from a liquid sample.

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