Particle Dynamics in Inertial Microfluidics: Review of Forces and Channel Design Principles

This paper aims to introduce readers and future researchers to the field of inertial microfluidics, presenting key principles, forces, and practical applications. By analyzing over 40 studies, the work systematizes the basic hydrodynamic mechanisms influencing particle motion in microchannels: inertial lift force, Dean drag force, and centrifugal force. The theoretical framework explains the role of dimensionless parameters, Reynolds number and clogging ratio λ, in determining stable particle positions and separation efficiency. A tabular overview summarizes the performance of each geometry, straight, curved and serpentine, and highlights their strengths and limitations. Major challenges include minimizing clogging in narrow channels, scaling throughput for industrial volumes, and adapting systems for complex biological samples like blood or environmental mixtures for microplastic removal. Future research directions should focus on hybrid geometries combining straight and curved segments to balance resolution and throughput, numerical optimization using machine learning algorithms to predict particle trajectories, and applications in emerging fields such as single-cell analysis or nanomaterial synthesis. By linking theoretical models, experimental validations, and industrial requirements, this paper serves as a practical guide for researchers designing inertial microfluidic systems tailored to specific separation tasks.