Picoliter droplet array based on bioinspired microholes for in situ single-cell analysis

Area of Science:

• Biotechnology
• Microfluidics
• Analytical Chemistry

Background:

• Microdroplet arrays are crucial for biochemical and medical analyses.
• Existing methods for droplet generation face limitations in precision and scale.

Purpose of the Study:

• To develop a novel method for generating picoliter droplet arrays for single-cell analysis.
• To leverage physical structure and interface properties for droplet formation.

Main Methods:

• A polydimethylsiloxane (PDMS) chip was fabricated using a micromachined glass mold.
• Droplet generation was achieved by exploiting wetting behavior in microholes with splayed sidewalls via liquid smearing.
• Picoliter droplet arrays were characterized for droplet volume and density.

Main Results:

• Successfully generated 0.9 picoliter droplet arrays with a relative standard deviation (RSD) below 6.3%.
• Achieved a high droplet density of 49,000 droplets/cm².
• Demonstrated the feasibility for bacterial single-cell analysis through bacteria separation and in situ propagation.

Conclusions:

• The proposed method offers a robust and efficient way to produce high-density picoliter droplet arrays.
• This technique is suitable for single-cell analysis, particularly for bacterial studies.
• The physical structure-based approach provides a scalable solution for microdroplet generation.