WITH just a PC and a webcam you might soon be able to carry out multiple medical diagnostic tests in the comfort of your own home.
It鈥檚 all thanks to today鈥檚 computer screens, which emit such crisp, bright colours that they are pure enough to use in diagnostic tests. Simply holding a grid of samples and reagents up to a computer screen that is displaying a sequence of colours, and using a webcam to analyse the light that passes through the grid, will make it easy to carry out several tests at once.
Many medical checks, such as measuring blood glucose levels and testing for pregnancy, can be done by mixing a body fluid, usually blood or urine, with a chemical and looking for a colour change. Labs can test for a range of conditions at once by adding drops of the appropriate fluid to a number of wells in a grid, each containing a different reagent. But checking the results can be costly and time-consuming. To get an accurate measurement of the colour change, laser light is shone through each well and the amount absorbed is recorded by a detector.
Advertisement
A team of physicists led by Daniel Filippini at Link枚ping University in Sweden reckon there is a far easier way. They added human cancer cells to a grid of 30 wells, each filled with varying concentrations of two anti-cancer drugs. A drop of a yellow salt that turns blue in the presence of living cells was then added. By checking which wells remain yellow, the test reveals what dose of drugs is needed to kill the cancer cells.
Rather than use a laser to measure the colour of each well, the team use a computer screen that displays a number of test-specific colours. The grid is pressed against the screen and the light passing through the wells is recorded with a standard webcam (see Graphic). The video clip from the webcam can be analysed to check the light absorption at each grid position.
The new program revealed the same colour changes as the far more expensive laser-based system (Chemical Communications, 2003, p 240). Filippini says this is because the ultra-narrow wavelengths of lasers are not crucial to many medical tests. 鈥淥ften, you just need to detect a small set of colours,鈥� he says.
Filippini now hopes to commercialise the idea, starting with cholesterol monitoring tests and sperm counts, and progressing to some DNA tests.