Reusable Embedded Microcoils for Magnetic Nano-Beads Trapping in Microfluidics: Magnetic Simulation and Experiments

In this study, a microfluidic chip with integrated coil was designed and fabricated for the aim of effectively trapping magnetic nanobeads (Adembeads^®, 300 nm) and measuring the chip's temperature during the working time. In addition, a reversible technique of bonding Polydimethylsiloxane (PDMS) channels was presented. This bonding process used a coating layer of CYTOPproduct as a protection, insulation and low-adhesion layer. The reversible packaging technique allows the bottom substrate to be reused, possibly equipped with sensors, and to use a disposable microchannels network. The FE method was employed to calculate the magnetic field and power consumption by the ANSYS^® version 12.1 software. Merit factors were defined in order to synthetically represent the ability of the simulated coil to trap beads for a unit power consumption, i.e. a given heat generation. The simulation results propose a new approach to optimize the design criteria in fabricating planar microcoils. The optimal microcoils were fabricated and then used to realize a magnetic immunoassay in a microfluidic chip. The aim was to integrate these microcoils into a lab-on-chip and obtain a fast and highly sensitive biological element detection.