Microfluidic Mixing and Analog On-Chip Concentration Control Using Fluidic Dielectrophoresis

Area of Science:

• Microfluidics
• Bioengineering
• Chemical Engineering

Background:

• Microfluidic platforms offer advanced on-chip processing for diverse applications.
• A lack of active microscale mixing methods hinders real-time control of solute concentrations.
• Current methods often require multiple fluid handling steps for varying concentrations.

Purpose of the Study:

• To present a novel electrokinetic method for active microfluidic mixing.
• To demonstrate dynamic control of on-chip solute concentrations in real-time.
• To reduce the complexity of microfluidic fluid handling for concentration-dependent applications.

Main Methods:

• Utilized fluidic dielectrophoresis for active mixing in microfluidic channels.
• Co-flowed three electrolyte streams (two conductive, one low-conductive) in a tri-laminar junction.
• Employed an electrode array to electrokinetically deflect outer streams into the central flow.

Main Results:

• Successfully demonstrated active mixing of laminar fluids using electrokinetic forces.
• Showcased the ability to dynamically control on-chip concentrations from a single inlet.
• Established a variable concentration gradient downstream using the actively mixed flow.

Conclusions:

• The novel electrokinetic method provides active microscale mixing and real-time concentration control.
• This approach simplifies microfluidic workflows by enabling variable concentrations from a single source.
• Offers a valuable tool for applications requiring precise and dynamic solute concentration management on-chip.