Highly efficient photonic PCR system based on plasmonic heating of gold nanofilms

The polymerase chain reaction (PCR) is a standard molecular method that has the potential to solve the need for accurate, viable, and immediate infectious pathogen detection at point-of-care (POC) centers in different fields such as pathogen identification, and forensics. In this work, we present a photonic PCR thermocycler that achieves strong optical absorption, more efficient gene amplification, and further improves the effect of temperature distribution through the PCR sample using two gold nanofilms (AuNFs) and a high-power light-emitting diode chip (LED). The photonic device achieved higher heating and cooling rates of 13.20 null°C/s and 7.92 null°C/s, respectively on average, with uniform and reliable temperature distribution throughout the sample with negligible deviations. During amplification cycles, maximum temperatures attained had variations less than 1 °C at 90 °C, less than 0.8 °C at 55 °C, and less than 0.5 °C at 72 °C, showing uniform heating which yielded more accurate and reliable results. Using the fabricated device, PCR amplification for a bacteria genomic DNA was performed in 7.5 minutes for 30 thermal cycles with a sample volume of 20 μL. Due to the device's simple configuration and increased heat transfer rates, this photonic platform will be a highly efficient choice for rapid POC applications in developing countries.