Compact, High-Performance Positive Magnetophoresis Chip With Integrated Patterned Magnet for Efficient Particle Trapping

In this work, we demonstrate a cost-effective, scalable, and rapid technique to fabricate a robust, high-performance on-chip positive magnetophoretic system. The system incorporates a thick patterned permanent magnet and microfluidic channel on a single polymethyl methacrylate (PMMA) substrate for on-chip manipulation of magnetic particles (MPs). Using the suitable patterning of the magnet, a spatially varying magnetic force is exerted onto the MPs in the channel, which is pertinent for capturing the MPs at specific locations. The device geometry is optimized using FEM simulations to prevent any blockage in the channel due to the accumulation of the MPs and ease the fabrication process. The ~1.5-fold enhancement in the trapping efficiency is observed upon lowering the flow rate from 15 $\mu \text{l}$ /min to $9~\mu \text{l}$ /min, leading to 94.5% trapping efficiency at a lower flow rate of $9~\mu \text{l}$ /min. [2022-0173]