"The CDs let you do thousands of biological sample tests quickly and in the field," says Michael Flynn, a NASA Ames scientist.

A liquid sample goes into a small opening near the center of the CD. A machine spins the disc to spread the sample fluid through tiny, capillarylike pipes and valves toward the outer edges. Special dyes in the CD fluoresce when exposed to certain proteins and particular portions of DNA in a sample. A light in the machine illuminates the disc while a microscope and digital camera image the glowing test sample after it stops spinning. "There are already thousands of fluorescent tests for conducting biological tests on bacteria, protein, and viruses," says Flynn. "The lab-on-a-CD system lets us automate a process that traditionally was time consuming and expensive." In the future, researchers would like to add a multidisc changer so they can test several CDs simultaneously.