Author(s)

T. PARDY, T. RANG & I. TULP

Abstract

The number of disposable molecular diagnostics tests in the IVD market has been growing rapidly and is bound to continue to grow in the near future. The internal complexity of these rapid tests increases with the complexity of the diagnostic assay implemented by them. Some assays require precise temperature control (±1°C –5°C) for an extended time (i.e. 15–60 minutes) for the reactions involved to run properly. Microheating components in them must meet strict criteria with respect to power con- sumption, physical size and cost. The proposed finite element model is intended to provide tools for in silico validation of device designs (geometries, structural materials), as well as to help in the interpretation of heat transfer processes inside the thermal system present in a molecular diagnostics device. The proposed model was developed for and validated with polyimide etched foil heating elements actively controlled via a mini-thermostat. The thermostat was designed for battery-based operation and implemented with open-source hardware (Arduino-compatible). Plastic test structures were created that emulated disposable Lab-on-a-Chip devices with microfluidic channels to hold liquid volumes on the scale of 0.1 mL. The experimental setup was demonstrated to maintain target temperatures over at least 30 minutes with at least ±1°C around the set point operated from batteries. Physical parameters of the resistive heating element used were fed into the finite element model and simulation results compared to the performance of the aforementioned experimental setup.

Keywords

computer aided design, finite element modelling, lab-on-a-chip, microfluidics, microcontrollers, resistive heating