High-Throughput Microfluidic Sorting of Live Magnetotactic Bacteria

Area of Science:

• Biotechnology
• Microbiology
• Nanotechnology

Background:

• Synthetic production of magnetic nanoparticles (MNPs) with uniform properties is challenging.
• Magnetotactic bacteria (MTB) naturally produce homogenous magnetosomes, making them ideal for MNP production.
• Current methods for selecting MTB with specific magnetic properties are limited, hindering large-scale MNP production.

Purpose of the Study:

• To develop a high-throughput magnetic microfluidic platform for separating MTB based on magnetic content.
• To enable the selection of MTB strains for optimized MNP production.
• To facilitate the study and application of genetically engineered MTB.

Main Methods:

• A magnetic microfluidic device combined with transient cold/alkaline treatment to temporarily reduce flagellar motion.
• Separation of MTB based on their magnetic content without compromising viability or biomineralization.
• High-throughput sorting of wild-type Magnetospirillum gryphiswaldense (MSR-1) and mutants.

Main Results:

• The platform achieved high-throughput separation (25,000 cells/min) with 80% sensitivity and 95% purity for MSR-1 strains.
• This represents a 25-fold increase in throughput compared to previous magnetic microfluidic platforms.
• The device successfully isolated Magnetospirillum magneticum (AMB-1) mutants with varying magnetosome numbers.

Conclusions:

• The developed magnetic microfluidic technology significantly enhances the selection and analysis of MTB.
• This facilitates the use of MTB as biological factories for controlled, large-scale MNP production.
• The technology is valuable for microbiologists, chemists, and bioengineers interested in biomineralization, directed evolution, and magnetogenetics.