A system for bar-coding DNA using brilliant crystals called quantum dots could revolutionize our ability to identify genes in the human genome.

A group at Indiana University in Bloomington has developed a way to embed quantum dots in tiny Styrofoam-like beads attached to DNA to create unique labels. The paper
appears in Nature Biotechnology.

The dots are semiconductor crystals of cadmium selenide wrapped in shells of zinc sulfide and measure just nanometres in diameter. This core/shell configuration squeezes the semiconductor charge carriers (electrons and their positive ounterparts called holes) into an artificially small space. When excited by a laser, the carriers recombine to emit light.
Perhaps the most promising near-term application is in proteomics, the science of matching proteins to corresponding genes.