Development of Temperature Control Solutions for Non-Instrumented Nucleic Acid Amplification Tests (NINAAT)

Non-instrumented nucleic acid amplification tests (NINAAT) are a novel paradigm in portable molecular diagnostics. They offer the high detection accuracy characteristic of nucleic acid amplification tests (NAAT) in a self-contained device, without the need for any external instrumentation. These Point-of-Care tests typically employ a Lab-on-a-Chip for liquid handling functionality, and perform isothermal nucleic acid amplification protocols that require low power but high accuracy temperature control in a single well-defined temperature range. We propose temperature control solutions based on commercially available heating elements capable of meeting these challenges, as well as demonstrate the process by which such elements can be fitted to a NINAAT system. Self-regulated and thermostat-controlled resistive heating elements were evaluated through experimental characterization as well as thermal analysis using the finite element method (FEM). We demonstrate that the proposed solutions can support various NAAT protocols, as well as demonstrate an optimal solution for the loop-mediated isothermal amplification (LAMP) protocol. Furthermore, we present an Arduino-compatible open-source thermostat developed for NINAAT applications.