A Simple Point-of-Care Device for Temperature Control of Multiple Reactions During Recombinase Polymerase Amplification

Abstract

For individuals with infectious diseases, early and accurate diagnosis is critical. A rapid diagnosis allows for prompt and effective treatment and increases the chance of a full recovery without complications. Additionally, when containing a wide-scale infectious disease outbreak, circumstances are significantly improved by the ability to test the populace frequently, swiftly, and affordably. Regarding specificity and sensitivity, nucleic acid amplification tests (NAAT) are one of the best options for diagnosing infectious diseases. Historically, polymerase chain reaction (PCR) has been used, but complex thermocycling and complicated PCR protocols have often limited PCR to clinical settings. Due to increased simplicity, the isothermal NAAT recombinase polymerase amplification (RPA) has the potential to deliver reliable Point-of-Care (POC) diagnostics in low-resource settings. When designing POC devices for isothermal NAATs, creating isothermal temperature conditions is perhaps the most significant challenge. This work presents a flexible and robust device capable of incubating 3 RPA reactions for simultaneous amplification in conditions conducive to POC testing. The device costs ∼$60 USD to construct and is easy to assemble. A battery-powered polyimide thin-film resistive heater provides energy, and the device only requires power for a fraction of the total incubation time. The device uses a phase change material (PCM) to regulate temperature to avoid the complexity of a microcontroller. RPA reactions were successfully incubated for 30 min using the device.