Multi-Vortex Regulation in a Simple Semicircular Microchannel with Ordered Micro-Obstacles for High-Throughput Buffer Exchange

Microfluidics
is an emerging technology for buffer exchange
in
bioprocessing applications. However, achieving buffer exchange with
simplicity of operation and high throughput in a straightforward channel
design remains a challenge. This study presents a novel semicircular
microchannel design that allows for the deterministic regulation of
helical and Dean vortices through geometric confinement. By incorporating
micro-obstacles into semicircular microchannels with large dimensions
(900 μm wide and 100 μm high), we observe a substantial
enhancement in secondary flows, leading to a unique fluid distribution
across a wide range of flow rates. This design enables a high particle
separation efficiency (>96.27%) coupled with a low fluorescein
purity
(<4.46%) at a high throughput of 3 × 106 particles/min.
The proposed methodology, characterized by ease of production (simple
semicircular microchannels with large dimensions), user-friendly operation
(uniform flow rates in both sheath and sample inlets), and efficient
buffer exchange capabilities (typically 3 mL min–1), demonstrates significant potential for advancing microfluidic
systems in biological and biomedical research.