For individuals with infectious diseases, early and accurate diagnosis is critical. A rapid diagnosis allows for prompt and effective treatment to be administered and increases the chance for a full recovery without complications. Additionally, when containing a wide-scale outbreak of infectious disease, circumstances are significantly improved by the ability to test the populace frequently, swiftly, and affordably. In terms of specificity and sensitivity, nucleic acid amplification tests (NAAT) are one of the best options for diagnosing infectious diseases. Historically, the polymerase chain reaction (PCR) has been used, but the complex thermocycling and complicated protocol of PCR have often limited PCR to clinical settings. Due to increased simplicity, isothermal NAATS present a better opportunity to create diagnostic tests deployed at a Point-of-Care (POC) level. Specifically, loop-mediated isothermal amplification (LAMP) and recombinase polymerase amplification (RPA) have the potential to deliver reliable POC diagnostics in low-resource settings. When designing POC devices for these NAATs, creating isothermal temperature conditions is perhaps the most significant challenge. This work presents a flexible device capable of incubating either LAMP or RPA in conditions conducive to POC testing. The flexibility in operating conditions comes from two factors. Firstly, the energy is provided by a battery-powered polyimide thin-film resistive heater. The voltage drop across the heater can be changed depending on the application, but the device does not rely on a microcontroller, which can add to the cost and intricacy. Secondly, a phase change material (PCM) is used to maintain isothermal conditions via latent energy storage. Usually, chemical heating is regulated via a PCM, and resistive heating is regulated via a microcontroller. This work aimed to combine advantageous elements of these two common methods in a novel way. When creating this device, different heating elements, PCM volumes, voltage drops, and power sources were tested and optimized for LAMP and RPA. The resulting device can operate at 58-65°C for ≥60 minutes or 35-42°C for ≥30 minutes and perform LAMP or RPA, respectively.

Portable device for temperature control during isothermal nucleic acid amplification tests for point-of-care diagnostics

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.