CD players have been overshadowed by MP3 files in the entertainment world, but in the biology lab, they could be the wave of the future. A team from Spain has developed a technique for studying biological samples using a CD and a CD player. By fabricating aluminum optical nanosensors on the surface of a standard polycarbonate CD, the researchers created a device that can detect biomolecules; the signals are read by the CD player. The group was led by the Universidad Politécnica de Madrid in collaboration with the Universidad Complutense de Madrid and the Universidad Politécnica de Valencia. In their experiments, they drilled 250-nm nanohole arrays into 100-nm-thick aluminum, which was deposited onto a conventional CD. The laser source of the CD player, an optical device based on surface plasmon resonance, scans the CD’s surface and “optically interrogates, by either reflection or transmission, each element of the microarray,” according to the researchers. This configuration can detect biomolecules without markers or labels so testing can be performed in real time, something not possible with existing specialty devices used for biological or clinical analysis. Investigators have found CDs to be an efficient platform for biosensing because they support high-density microarray assays. They also have an enormous amount of storage space. Because it uses aluminum rather than a more expensive metal such as gold or silver, the new technique has proved to be efficient and cost-effective. And given the ease of use and portability of a CD and player, the method can simplify analysis and testing at the point of care. The research is published in Plasmonics. For more information, visit: www.upm.es.