(FORTUNE Magazine) – Hayward, Calif. Founded 1998

Call it the newest form of California hyphenate. But is Quantum Dot a nano-biotech or a bio-nanotech? Either way, the company manipulates molecules to make brilliantly colored crystals called quantum dots that can illuminate biological structures on a slide or--in the future--in a body. The "dots" attach to the cells and light up different parts, creating wildly hued, paisley-shaped images that are valuable for diagnostic and drug-research purposes. Quantum dots are brighter and last dramatically longer than traditional evanescent fluorescent dyes, effectively enabling researchers to move from taking snapshots of cells to watching them in action. Such benefits have helped generate 1,000 customers and several million dollars in revenues for the company 18 months after its first product debuted. Co-founder and chairman Joel Martin, 47, a former radiology professor, is expanding the company into new areas, including a partnership to develop kits--akin to home pregnancy tests--that will let you check yourself for prostate cancer or heart disease. --Nicholas Varchaver