Efficient magnetic microbeads trapping using lab-on-chip magnetic separator

Abstract

Lab-on-Chip (LoC) magnetic separation is a simple and effective method in separating bioparticles labelled with magnetic microbeads in microfluidics flow condition. In this work, trapping efficiency of magnetic microbeads using LoC magnetic separator and a microfluidics channel with chamber design is determined. The polydimethylsiloxane (PDMS) microfluidics channel was designed with an inlet, an outlet and a circular trapping chamber at the center. Standard soft lithography technique was used to replicate the PDMS microfluidics channel from the SU-8 mould. In a continuous hydrodynamics flow of 1.0 μL/min, trapping efficiency of 99.5 % and 94.9 % for 4.5 μm and 2.5 μm magnetic microbeads respectively was achieved. Flow analysis using COMSOL Multiphysics has been conducted in predicting the possible location of the magnetic beads trapping inside the microfluidics channel. The trapping is possible whenever the magnetic force is larger than the drag force experience by the magnetic microbead. The microfluidics channel with chamber design had facilitated low hydrodynamics drag force on the magnetic beads and resulted high efficiency trapping. Therefore, the development of this LoC magnetic separator may be promising to be utilized for biological studies and point-of-care testing (POCT) applications.