Comparative numerical and experimental evaluation of 3D-printed micromixers for biotechnological applications.

Micromixers are essential in microfluidic-based biotechnology and diagnostics, where reproducible reactions and rapid mass transfer are crucial. Although many geometries exist, consistent comparison across dimensions, fabrication methods, and evaluation techniques remains challenging. In this study, we present a comparative analysis of six micromixer designs, focusing on mixing efficiency, pressure drop, shear stress, and the energy-dissipation rate. The devices were fabricated using high-definition 3D printing and studied experimentally and with high-resolution computational fluid dynamics (CFD) simulations. Tests covered a wide Reynolds-number range (Re = 0.1-200). At both ends of this range, most designs achieved adequate mixing. The greatest disparities emerged in the intermediate regime (Re = 1-50), with the Kenics geometry outperforming all other designs. Our grid-optimized CFD results matched experimental trends and quantified local shear and energy-dissipation rates. Live/dead assays using an industrially relevant Chinese hamster ovary (CHO) cell line showed unchanged viability immediately after mixing and during subsequent cultivation. By combining experimentally validated CFD predictions, systematic grid-optimized assessment, and biological validation within a single framework, this study establishes a consistent basis for comparing micromixer designs and selecting those that match desired combinations of mixing performance, pressure drop, volume, shear stress, and the energy-dissipation rate.