Digital Microfluidics for Single Bacteria Capture and Selective Retrieval Using Optical Tweezers.

Area of Science:

• Microbiology
• Biotechnology
• Bioengineering

Background:

• Selective retrieval of microbial cells is crucial for research but traditional methods like fluorescence activated cell sorting (FACS) and optical tweezers (OT) have limitations.
• FACS allows cell sorting but not dynamic behavior tracking, while OT are typically confined to complex microfluidic systems.

Purpose of the Study:

• To develop and demonstrate a novel digital microfluidics (DMF) platform integrated with optical tweezers (OT) for the selective isolation, relocation, and proliferation of single bacterial cells.
• To enable continuous imaging for evaluating dynamic cell behavior alongside selective retrieval.

Main Methods:

• Magnetic beads coated with Salmonella Typhimurium-specific antibodies were used to capture single bacterial cells on a DMF platform.
• Optical tweezers (OT) were employed to select and relocate individual antibody-bound bacteria to different microwells for isolation and proliferation.
• An agar patch was used to facilitate the proliferation of the relocated bacteria for downstream analysis.

Main Results:

• The integrated OT-DMF platform successfully enabled the selective trapping and retrieval of single fluorescent Salmonella Typhimurium cells.
• Relocation of selected bacteria to new microwells for proliferation was achieved with high precision.
• Continuous imaging allowed for the evaluation of dynamic cell behavior during the process.

Conclusions:

• The developed OT-integrated DMF platform provides a powerful tool for single-cell isolation, retrieval, and proliferation of specific bacteria.
• This technology overcomes limitations of traditional methods, enabling detailed analysis of microbial populations and individual cell dynamics.
• The platform facilitates downstream analysis of selected bacterial cells of interest.