Nature Photonics brought public attention to a report in Lab Chip that claims a regular old DVD player, with a few basic modifications, could provide quick and accurate tests for HIV — and for many other diseases, as well.
The technology requires three major modifications. The first is the addition of a new photodiode, one designed to capture the sort of information we require. There aren’t currently any specifics about just what sort of diode is needed, but they aren’t expensive or difficult to install. Some hot glue and a single wire ought to be enough. After that, we need to modify the player further by loading it up with special lab software; that’s another quick, cheap fix, though one that would seem to require slightly more modern DVD players with more robust internal computers. Finally, we require specialized disposable, multilayer, semi-transparent polymer discs. These custom discs are the only glaring problem with DVD-diagnosis, as they would need to be specially made for binding a specific disease marker. For HIV, this would mean binding the CD4+ helper T-cells, and using their abundance as a reference for the presence of HIV.
Once you’ve got your modded DVD player and custom CD4-binding discs, you’re ready to go. Loading should be as easy since the setup can take untreated blood straight from a patient, and then the process begins. The DVD reader’s laser shines down through the blood and disc to be recorded by our new photodiode, and as the disc spins we create a record two-dimensional picture of the light that makes its way through to the other side. Thanks to the centrifuge-like spinning of the disc, only bound T-cells should remain to block the transmission of the laser. More dots means more T-cells, means the patient is less likely to carry HIV. That’s not a perfect test, of course, and wouldn’t detect HIV in the absolute earliest stages of infection, but it could still notice drops in T-cell counts months before the patient would otherwise begin to notice health effects.
This technique need not be limited to HIV, but that’s where a dramatic price drop would have the most immediate and powerful effect. Of course, every branch of research will benefit from a low-cost solution to a traditionally cloistered experimental process, especially for seat-of-the-pants assays. We might not be publishing too many papers in Science that rely on DVD assays for proof, but the preliminary research that justifies such high-budget experiments could be made far quicker and cheaper with a $200 basement alternative to flow cytometers, which do much the same job and regularly cost $25,000 or more.
It’s unfortunate that the assay discs must be made anew for each desired target cell or molecule, and it’s currently unclear whether the discs will be reusable. Still, with a purported 1 µm resolution, this tech could revolutionize frontier aid work, and empower researchers everywhere with real, low-cost solutions today.
Source: Extreme Tech