Print, spit, and play

A team at the University of California, San Diego have developed a cheap way of testing blood or other biological samples for particular proteins and eventually even genes. At present, the machines to identify molecules in biological samples cost hundreds of thousands of dollars. When CD's are played on a computer CD drive, the computer automatically notes the errors, which are normally thought of as a bad thing. In this system, you inkjet print an alcohol-based mixture of protein receptors onto the CD from a regular printer with a special cartridge. You dunk it in the biological sample, clean it, and then play it on the computer. The computer counts an error every time a protein molecule binds to the surface and blocks the laser in the CD drive. These protein molecules are glued to the surface, so they don't wash off when you clean the disk. You can literally hear the molecules, as they've tried playing music CDs to hear the errors. For example they were able to detect an enzyme that turns starch into sugar. They had someone spit onto a receptor-printed CD of Beethoven's Fifth symphony, clean it up, and then listen for the differences in the music. This is a little like the artists who grow fungus on their music CDs and photo CDs and then play them for the groovy results of lasers being diffracted by fungus microfibres growing from spilt beer. For more accurate readings the team have developed software to run on linux home PCs, comparing the errors and bytes on the CD before and after exposure to a biological sample. They plan to release the software as open source free to download from the net, so that anybody can play with it.