DNA-library assembly programmed by on-demand nano-liter droplets from a custom microfluidic chip

Area of Science:

• Synthetic Biology
• Microfluidics
• Molecular Biology

Background:

• Programmable nanoliter-scale DNA processing in microfluidic chips is crucial for synthetic biology.
• Active microvalve chips present fabrication and operational complexities.
• A need exists for simpler, passive microfluidic systems for DNA manipulation.

Purpose of the Study:

• To demonstrate the utility of a passive microfluidic chip for customizable nanoliter-scale DNA processing.
• To establish a proof of principle for generating DNA test libraries in a one-member-per-droplet format.
• To showcase the device's capability for controlled droplet generation, mixing, and reaction control.

Main Methods:

• Utilized a passive microfluidic device for combinatorial droplet generation and mixing.
• Employed standard DNA assembly techniques (e.g., Gibson assembly) compatible with isothermal on-chip operation.
• Verified droplet sequence control, mixing performance, and enzymatic assembly using dyes, fluorescent DNA, PCR, gel electrophoresis, and DNA sequencing.

Main Results:

• Successfully generated a DNA test library with individual members in nanoliter droplets.
• Demonstrated precise control over output droplet sequences and mixing efficiency.
• Verified the functional enzymatic assembly of DNA components within the microfluidic system.

Conclusions:

• A passive microfluidic chip offers a readily fabricated and operable solution for nanoliter-scale DNA processing.
• The device enables customizable DNA library production for applications in synthetic biology.
• The approach is scalable for generating larger DNA libraries through combinatorial input expansion.