Continuous Flow vs. Static Chamber μPCR Devices on Flexible Polymeric Substrates

This paper was presented at the 4th Micro and Nano Flows Conference (MNF2014), which was held at University College, London, UK. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute, ASME Press, LCN London Centre for Nanotechnology, UCL University College London, UCL Engineering, the International NanoScience Community, www.nanopaprika.eu.Two types of μPCR devices, a continuous flow and a static chamber device, fabricated on flexible polymeric substrates are compared in the current computational study. Laminar flow, heat transfer in both solid and fluid, mass conservation of species, and reaction kinetics of PCR are coupled using COMSOL. The comparison is performed under same conditions; same material stack (based on flexible polymeric films with integrated microheaters), same species initial concentrations, amplification of the same volume of fluid sample, and implementation of the same PCR protocol. Performance is quantified in terms of DNA amplification, energy consumption, and total operating time. The calculations show that the efficiency of DNA amplification is higher in the continuous flow device. However, the continuous flow device requires (~6 times) greater energy consumption which is justified by the smaller thermal mass of the static chamber device. As regards the speed, the total time required for the static chamber μPCR is comparable to the time for the continuous flow μPCR

A Passive Micromixer for Bioanalytical Applications

This paper was presented at the 4th Micro and Nano Flows Conference (MNF2014), which was held at University College, London, UK. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute, ASME Press, LCN London Centre for Nanotechnology, UCL University College London, UCL Engineering, the International NanoScience Community, www.nanopaprika.eu.Three passive micromixers with different geometries, i.e. zigzag, spiral, and split and merge (SaM) with labyrinthine channels, are compared with respect to their mixing efficiency by means of a computational study. The specifications are imposed from flexible printed circuit (FPC) technology which is used for their fabrication and from the applications to be implemented, i.e. the mixing of biochemical reagents. The computations include the numerical solution of continuity, Navier-Stokes, and mass conservation equations in 3d by ANSYS Fluent. The highest mixing efficiency is calculated for the SaM micromixer with the labyrinthine channel. Compared to a linear micromixer, the spiral micromixer improves the mixing efficiency by 8%, the zigzag by 11%, and the SaM by 92%; the diffusion coefficient of the biomolecule is 10-10 m2/s, the Reynolds number is 0.5, and the volume of each micromixer is 2.54 μl. The best of the three designs is realized by FPC technology and is experimentally evaluated by fluorescence microscopy