Metal-pad-enhanced resistive pulse sensor reveals complex-valued Braess paradox.

Area of Science:

• Physics
• Electrical Engineering
• Fluid Dynamics

Background:

• Resistive pulse sensing typically measures increased channel impedance due to nonconductive particles.
• Conventional understanding assumes particle presence obstructs current flow, raising resistance.

Purpose of the Study:

• To report and explain a counterintuitive phenomenon in microfluidic resistive pulse sensing.
• To introduce and analyze the complex-valued Braess paradox (CVBP) in this context.

Main Methods:

• Experimental investigation using a microfluidic resistive pulse sensor.
• Development of theoretical models to explain the observed phenomenon.
• Validation through finite element simulations and lumped-element circuit modeling.

Main Results:

• Observed that nonconductive particles unexpectedly decrease channel impedance.
• Demonstrated that this effect can be explained by the complex-valued Braess paradox (CVBP).
• Corroborated experimental findings with theoretical models and simulations.

Conclusions:

• The complex-valued Braess paradox (CVBP) offers a new explanation for particle-induced impedance changes in resistive pulse sensors.
• This discovery has potential implications for advancing resistive pulse sensing technology and related fields.
• The study highlights the importance of considering complex network effects in microfluidic sensing.