A New Way to PCR Could Get You Results in Minutes Instead of Hours

Whether you are using PCR to clone, assess gene expression, or diagnose disease, modern science is difficult to imagine without PCR. Scientists at UC Berkeley have rethought how we heat and cool samples during PCR, shortening a process that once took hours to minutes.

Standard PCR machines use Peltier elements to heat and cool reactions, a process that is limited in speed and requires a lot of power. This poses a challenge for diagnostic point-of-care (POC) applications where results are needed in minutes and tools need to be small, easy to use, and energy efficient so that they can be used in any setting. To address POC needs, Song et al. developed a PCR machine that uses off–the-shelf LEDs to excite electrons in a thin gold film. The excited electrons oscillate, emitting heat in a process known as plasmonic photothermal heating. When the LEDs are turned off the electrons stop oscillating and the temperature drops rapidly. Using this photonic PCR machine, Song et al. were able to complete 30 cycles from 55°C to 95°C in five minutes instead of hours using two to three watts instead of the hundreds of watts required by a standard thermal cycler.

Song and his colleagues in the BioPOETS group emphasize that their photonic PCR machine is not only faster and more energy efficient, the use of LEDs will also allow them to downscale the size of a PCR machine. The goal is to build a photonic PCR machine the size of a cell phone that can be used in the field to diagnose patients in a matter of minutes.

Source: University of California, Berkeley