Numerical Analysis of Annealing in an Annular Tube Using Nanoparticle-Enhanced Phase Change Material

The recent outbreak of a pandemic has driven microfluidics research toward reducing pathogen identification delays. Microfluidic polymerase chain reaction (PCR) modules enable efficient heat transfer and compact point-of-care applications but struggle with rapid temperature shifts. Nanoparticle-enhanced phase change materials (NePCMs) offer promising passive thermal management for improved DNA amplification efficiency. This study explores combining minichannels with NePCMs containing Al2O3 and CuO nanoparticles for stable annealing temperatures. Computational analysis of a continuous flow PCR pathway shows NePCM-bounded channels rapidly achieve and sustain optimal annealing conditions. A parametric study found that a 4 mm wide NePCM capsule for a 30 mm long channel achieves a stable isothermal region rapidly, and further experimentation showed that increasing concentrations of Al2O3 and CuO nanoparticles significantly reduce the annealing temperature. A NePCM with both types of nanoparticles (at volume fraction, Φ = 10%) outperforms the base PCM by increasing the isothermal region length by 30% to 50%. Among the nanoparticles, CuO extends the isothermal length by 10% to 12% more than Al2O3. Moreover, CuO achieves isothermal equilibrium faster than Al2O3, demonstrating superior performance compared to its counterpart. This study on thermal management using nanoparticles in thermocycler development shows potential for creating portable PCR devices for pathogen detection.