Turbocharged Thermal Cycling Leads to Ultrafast DNA Diagnostics

The ultrafast photonic PCR method uses plasmonic photothermal light-to-heat conversion via photon-electron-phonon coupling.

The scientists used thin films of gold that were 120 nm thick. The gold was deposited onto a plastic chip with microfluidic wells to hold the PCR mixture with the DNA sample. The light source was an array of off-the-shelf LEDs positioned beneath the PCR wells. The peak wavelength of the blue LED light was 450 nm, tuned to get the most efficient light-to-heat conversion. They were able to cycle from 55 °C to 95 °C 30 times in less than five minutes. They tested the ability of the photonic PCR system to amplify a sample of DNA, and found that the results compared well with conventional PCR tests.

Luke P. Lee, PhD, a professor of bioengineering, and senior author of the study said, “This photonic PCR system is fast, sensitive and low-cost. It can be integrated into an ultrafast genomic diagnostic chip, which we are developing for practical use in the field. Because this technology yields point-of-care results, we can use this in a wide range of settings, from rural Africa to a hospital emergency room.” The study was published on July 31, 2015, in the journal Light: Science & Application.

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