A new approach to design an efficient micropost array for enhanced direct-current insulator-based dielectrophoretic...

Area of Science:

• Biophysics
• Microfluidics
• Electrical Engineering

Background:

• Direct-current insulator-based dielectrophoresis (DC-iDEP) is a microfluidic technique utilizing electric field gradients from insulating posts for particle manipulation.
• Optimizing post array geometry is crucial for enhancing trapping efficiency and minimizing energy consumption.

Purpose of the Study:

• To establish a geometrical relationship for insulating post arrays that maximizes particle trapping efficiency.
• To minimize the required voltage for effective particle trapping, independent of particle type and medium.
• To introduce a novel figure of merit for optimizing DC-iDEP systems.

Main Methods:

• Finite element analysis using COMSOL Multiphysics to simulate various post array configurations (varying transversal/longitudinal distances and post radii).
• Development and application of a new figure of merit to quantify trapping performance.
• Experimental validation using polydimethylsiloxane (PDMS) microchannels and polystyrene particles.

Main Results:

• A post radius larger than the transversal distance significantly enhances trapping, with improvements ranging from 56% to 341% depending on the transversal distance.
• Numerical simulations showed a clear correlation between specific geometric parameters and trapping efficiency.
• Experimental results using 6-μm polystyrene particles validated the numerical findings, confirming the identified trends.

Conclusions:

• The proposed geometrical relationship and figure of merit enable optimized DC-iDEP for enhanced particle trapping.
• Reduced electric field requirements minimize Joule heating, preserving the viability of biological samples.
• The findings are geometry-dependent and broadly applicable to various particles and media, offering a versatile tool for microfluidic applications.