Rahim Esfandyarpour helped to develop the diagnostic “lab on a chip” Zahra Koochak/Stanford School of Medicine. Matt Reynolds. Your diagnostic kit is downloading. A “lab on a chip” system costs less than a penny to make and can test cell samples for diseases such as tuberculosis, malaria and cancer.
The technology could help with early detection of diseases in the developing world, where lack of access to equipment can lead to late diagnosis. “You can use it anywhere, as long as you have a printer,” says Rahim Esfandyarpour at Stanford University, who led the team that created the chips.
Each chip consists of a clear silicone chamber that houses a sample of cells for testing and a reusable electronic strip. The electronic strip can be printed onto flexible sheets of polyester using a regular inkjet printer and conductive nanoparticle ink. Users can download different designs for the strip, which let it test for different things. The whole printing process takes just 20 minutes.
Draw and print
Applying an electric charge across the strip causes cells in the sample to separate according to their electrical properties, allowing researchers to isolate certain cell types. This could be used to separate out tumour cells circulating in the bloodstream, for example, and catch certain cancers at an early stage.
If researchers want to switch experiments and start counting cells instead of separating them by type, they can simply pop in a different electronic strip. “You can just draw [the strip] out on the computer and print it,” Esfandyarpour says. In the future, he’d like to see a shared online database of different designs that can easily be downloaded, printed out and put to use.
This type of kit could be used by any laboratory that has an inkjet printer and conductive ink, says Julien Reboud at the University of Glasgow. There have been other “lab on a chip” designs over the past couple of decades, he says, but it can be difficult to get the technology to clinics and research laboratories in the developing world.
Reboud warns that the device is not a replacement for all of the equipment needed in sample analysis. At the moment, the new chip requires users to pump the fluid sample into the device using a commercial syringe pump, but some labs may not have this technology readily available. “People tend to forget about how the sample gets in and what needs to be around that particular device,” he says.