Experimental and numerical characterization of magnetophoretic separation for MEMS-based biosensor applications

Area of Science:

• Biomedical Engineering
• Microfluidics
• Biophysics

Background:

• Magnetophoresis is crucial for bioMEMS applications like biosensors.
• Microfluidic devices enable precise manipulation of biological entities.
• Magnetic microspheres facilitate magnetophoretic separation.

Purpose of the Study:

• To experimentally and numerically analyze magnetophoretic capture of magnetic microspheres in microfluidics.
• To identify critical operating conditions and parameters governing particle capture and trajectories.
• To evaluate magnetophoretic capture efficiency and its dependence on dimensionless numbers.

Main Methods:

• Experimental analysis using bright-field microscopy.
• Numerical simulations of particle trajectories in a microfluidic channel.
• Investigation of magnetophoresis under an external magnetic field.

Main Results:

• A critical capture parameter, Pi(crit), proportional to the magnetic to viscous force ratio, was identified.
• Particle trajectories are governed by a similar dimensionless parameter, pi.
• Magnetophoretic capture efficiency correlates with a specific dimensionless number, Pi(*).

Conclusions:

• The study provides a framework for selecting operating parameters in microfluidic magnetophoretic systems.
• Numerical and experimental results show good agreement, validating the proposed parameters.
• Findings aid in predicting and optimizing the performance of microfluidic separators.