The average home-entertainment disc player is good for audio and video, but a talented hacker could apparently expand the machine’s horizons to include medical diagnoses and chemical tests.
Normally, the devices’ lasers scan a CD (compact disc) or DVD (digital video disc) for microscopic bumps that encode sounds and images. Analytical chemist Angel Maquieira of the Polytechnic University of Valencia in Spain and his colleagues reasoned that the system could be modified to detect certain chemicals in lab samples as well, and would be much cheaper than the $40,000-to-$80,000 portable microarray detectors usually used.
The scientists coated blank CDs with dots containing antibodies mixed with various chemicals. The antibodies were designed to darken if they came into contact with any of three pesticides in the chemical mixes. The team placed these discs in a CD player to which the researchers had added sensors that could detect changes in the intensity of light transmitted through the dots as they were scanned by the player’s laser. Normally, CD players detect only the presence or absence of reflected light. A computer hooked up to the player then read whether individual dots had darkened. In the Oct. 15 Analytical Chemistry, the team reports that the modified device detected concentrations of pesticides as low as 20 billionths of a gram per liter, a level of sensitivity comparable to that of current lab scanners.
Maquieira says that a converted disc player could run tests in home labs, at doctors’ offices, or even outdoors. The device could even help pharmaceutical companies rapidly assess the behavior of potential drugs, since up to 300,000 samples could be crammed onto a single disc.