Modeling Liquid‐Mediated Interactions for Close‐to‐Substrate Magnetic Microparticle Transport in Dynamic Magnetic Field Landscapes

ABSTRACT Understanding the on‐chip motion of magnetic particles in a microfluidic environment is key to realizing magnetic particle‐based Lab‐on‐a‐chip systems for medical diagnostics. In this work, a simulation model is established to quantify the trajectory of a single particle moving close to a polymer surface in a quiescent liquid. The simulations include hydrodynamic, magnetostatic, and Derjaguin–Landau–Verwey–Overbeek (DLVO) interactions. They are applied to particle motion driven by a dynamically changing magnetic field landscape created by engineered parallel‐stripe magnetic domains superposed by a homogeneous, time‐varying external magnetic field. The simulation model is adapted to experiments in terms of fluid‐particle interactions with the magnetic field landscape approximated by analytic equations under the assumption of surface charges. Varying simulation parameters, we especially clarify the impact of liquid‐mediated DLVO interactions, which are essential for diagnostic applications, on the 3D trajectory of the particle. A comparison to experimental results validates our simulation approach.