A sample-to-answer, real-time convective polymerase chain reaction system for point-of-care diagnostics

Timely and accurate molecular diagnostics at the point-of-care (POC) level is critical to global health. To this end, we propose a handheld convective-flow real-time polymerase chain reaction (PCR) system capable of direct sample-to-answer genetic analysis for the first time. Such a system mainly consists of a magnetic bead-assisted photothermolysis sample preparation, a closed-loop convective PCR reactor, and a wireless video camera-based real-time fluorescence detection. The sample preparation exploits the dual functionality of vancomycinmodified magnetic beads (VMBs) for bacteria enrichment and photothermal conversion, enabling cell pre concentration and lysis to be finished in less than 3 min. On the presented system, convective thermocycling is driven by a single-heater thermal gradient, and its amplification is monitored in real-time, with an analysis speed of less than 25 min, a dynamic linear range from 106 to 101 copies/mu L and a detection sensitivity of as little as 1 copies/mu L. Additionally, the proposed PCR system is self-contained with a control electronics, pocketsize and battery-powered, providing a low-cost genetic analysis in a portable format. Therefore, we believe that this integrated system may become a potential candidate for fast, accurate and affordable POC molecular diagnostics.