A researcher focused on portable, economic PCR has finally hit paydirt with a system that measures about 100mm x 60mm x 33mm and weighs just 90g.
Professor Pavel Neužil has been working closely with researchers in Singapore and China to achieve 10 minutes per 40 PCR cycles from a machine that is small and light enough to be carried in the palm of your hand.
In a previous system, researchers employed two lock-in amplifiers—one for a single fluorescence detection system and another for temperature measurement—which meant that fluorescence was monitored for as long as 2s.
The upgraded device uses just one lock-in amplifier to monitor the sample temperature and capture fluorescence from 4 samples. This significantly speeds up the system, enabling the 10 minutes for 40 PCR cycles mentioned earlier. And “the lock-in amplification makes system more robust and user friendly as no light shield is required,” said Neužil.
Figure 2: A cut-out illustration of the device that runs on a 12V source. The blue arrows show the optical path from an LED to the virtual reaction chamber. The green arrow shows the optical path of the fluorescence to the photodiode. For more details, read Neužil's paper here.
The end result of the labour is a system that measures about 100mm x 60mm x 33mm and weighs just 90g. Samples (200nL) are placed on a disposable glass cover slip covered with mineral oil to prevent water evaporation. This arrangement prevents sample-to-sample cross contamination—the glass element is disposable.
Figure 3: The PCR results are displayed on an LCD.
The PCR results are displayed on an LCD and can be transferred to a computer for further processing using a USB interface. The size, weight and low cost make the device suitable for use in remote clinics and as an educational tool.