Microfluidic Simulation Framework for Point-of-Care Diagnostics: Modeling Advection-Diffusion-Reaction Transport in Lab-on-Chip Systems

Point-of-care diagnostics (POCD) rely heavily on microfluidic lab-on-chip systems, yet their design process is often hindered by trial-and-error prototyping and inconsistent reproducibility. Efficient diagnostic performance requires a clear understanding of how advection, diffusion, and biochemical reactions jointly govern analyte transport at the microscale. This work presents a lightweight numerical framework for modeling solute behavior in microfluidic channels using the advection–diffusion–reaction equation. A finite-difference solver was applied to a 5 mm × 100 μm channel under physiologically relevant flow conditions, comparing three regimes: diffusion-only, advection + diffusion, and advection + diffusion + first-order reaction. Results show that high Péclet numbers (Pe ≈ 1000) drive plug-like transport with minimal lateral mixing, while Damköhler numbers near unity (Da ≈ 1) produce significant axial…