Metal-organic frameworks-based photonic PCR for ultra-fast real-time quantitative pathogen detection

Rapid and timely nucleic acid detection through polymerase chain reaction (PCR) is an urgent demand in epidemic prevention and control. However, conventional Peltier-based PCR instruments are too slow to meet this requirement. Herein, an ultra-fast photothermal real-time quantitative PCR (qPCR) system that integrates a metal-organic framework (MOF)-based photothermal membrane with a silicon-based microfluidic chip is constructed for rapid SARS-CoV-2 detection. After optimization of the synthesis temperature of zirconium-ferrocenyl (Zr-Fc) MOFs and the thickness of Zr-Fc MOF/SWCNTs (ZFC) membranes, the resultant ZFC-22 membrane exhibits excellent and robust photothermal performance with an ultra-fast heating rate of 60.3 °C/s, enabling a rapid heat generation rate. Subsequently, the ZFC-22 membrane is integrated into a custom-designed silicon-based microfluidic chip that not only enhances heat conduction but also effectively confines heat in the PCR microchannel via thermal-isolation grooves, thereby reducing heat loss. Finally, a photothermal real-time qPCR system consisting of photothermal modules, microfluidic chips, control modules, and fluorescence imaging modules is constructed, which completes 40 nucleic acid amplification cycles within 10 min with an excellent amplification efficiency (98.6%), a low limit of detection (10 copies/μL), and an extremely low average optical power (1 W/well).