Rapid membrane-based photothermal PCR for disease detection

Abstract

The worldwide incidence of deadly infectious diseases has increased in recent years. Therefore, a rapid and accurate nucleic acid diagnostic system is in high demand. Polymerase chain reaction (PCR) is the standard method for amplifying and quantifying nucleic acid biomarkers for disease detection. Although several rapid PCR systems have been developed to overcome the limitations of conventional PCR, such as post-processing for analysis, complicated handling, and highly specialized instruments, a new PCR testing approach is still required. In this study, we developed a rapid membrane-based photothermal PCR that enables quantitative fluorescence detection. It requires no post-PCR procedures and provides user-friendly micro-scale solution control and sample loading. Au nanostructure was deposited on the reaction pad as a light-to-heat converter for PCR thermocycling. The automatically controlled 785 nm light source heated a solution in the reaction pad with photothermal effect. The temperature of the reaction solution, which was absorbed in a membrane, was cycled 25 times between 63 °C and 95 °C within 6 min with a photothermal cycler. The amplified samples on the membrane were then quantitatively analyzed by measuring the fluorescence signal of intercalating SYBR dye within 12 min. DNA samples extracted from Staphylococcus aureus and unpurified cells were amplified and analyzed. This membrane-based PCR approach can provide easy connectivity with various membrane-based sample pre-treatment processes, and therefore the proposed procedure could be used as the basis for an all-in-one molecular diagnosis platform. This simple, rapid, and sensitive PCR device could also serve as the basis for advanced molecular diagnostics.