Automatic trajectory control of single cells using dielectrophoresis based on visual feedback

Area of Science:

• Biophysics
• Microfluidics
• Control Systems Engineering

Background:

• Dielectrophoresis (DEP) is typically used passively, limiting control over cells with similar characteristics.
• Existing active DEP systems often rely on offline computation for electric field generation.
• Real-time, automated control of dielectrophoretic actuation for cell trajectory manipulation is lacking.

Purpose of the Study:

• To develop and validate an experimental system for automatic trajectory control of T-lymphocytes using real-time dielectrophoretic actuation.
• To investigate an online model for computing dielectrophoretic forces based on cell properties and position.
• To implement a visual feedback controller for precise cell manipulation within a microfluidic chip.

Main Methods:

• An experimental bench was designed for studying automatic cell trajectory control via dielectrophoresis.
• An online model using Fourier series computed dielectrophoretic forces in real-time.
• A visual feedback controller operating at 120 Hz adjusted electric fields for trajectory control.
• Controller design prioritized maximizing DEP force while ensuring cell safety by limiting electric field strength.

Main Results:

• T-lymphocytes were successfully steered along various predefined trajectories within a microfluidic chip.
• Achieved cell manipulation speed was up to five times the cell's size per second.
• Demonstrated high trajectory accuracy with a mean error below 2 μm.
• Cell viability assays confirmed no adverse effects from the active DEP actuation.

Conclusions:

• The developed system enables precise, real-time, automated control of T-lymphocyte trajectories using active dielectrophoresis.
• The online force computation model and visual feedback controller are effective for dynamic cell manipulation.
• This approach offers a promising, non-harmful method for targeted cell positioning in microfluidic applications.