Microfluidic sorting of intrinsically magnetic cells under visual control

Area of Science:

• Biotechnology
• Microfluidics
• Cell Separation

Background:

• Magnetic cell sorting offers an alternative to fluorescent methods, with growing interest in magnetic cells for molecular control.
• Contamination-free magnetic separation is vital for studying naturally magnetic or engineered cells.

Purpose of the Study:

• To develop a robust and tunable microfluidic system for precise magnetic cell sorting.
• To achieve contamination-free separation of magnetic cells for downstream applications.

Main Methods:

• Utilized a microfluidic sorting system with tunable magnetic gradients (up to 1700 T/m) generated by reversible ferrofluid magnetization.
• Employed visual control and automated quantification with fluorescent markers to optimize sorting.
• Separated macrophages with magnetic nanoparticles and intrinsically magnetic magnetotactic bacteria.

Main Results:

• Achieved 90 ± 1% sorting efficiency for macrophages with magnetic dipole moments of 10 fAm².
• Successfully sorted magnetotactic bacteria with magnetic moments of 0.1 fAm².
• Demonstrated contamination-free separation by preventing sample contact with superparamagnetic material.

Conclusions:

• The microfluidic system provides a tunable and efficient method for magnetic cell sorting.
• This contamination-free approach is essential for characterizing naturally magnetic or bioengineered cells.
• The system advances magnetic cell separation for biotechnological and research applications.