A Microfluidic Digital Shutter of Liquid-Liquid Interface for Fabrication of Multifaceted Hydrogel Microfiber...

Area of Science:

• Soft matter physics
• Materials science
• Biomedical engineering

Background:

• Microfluidic devices offer potential for complex fluidic control.
• Precise fabrication of anisotropic hydrogel microparticles with programmable geometries remains a challenge.

Purpose of the Study:

• To introduce a programmable passive digital shutter mechanism for precise hydrogel microfiber fabrication.
• To achieve deterministic control over microfiber geometry using multiphase liquid-liquid interface dynamics.

Main Methods:

• Utilized a microfluidic platform with three fluids: two immiscible phases for the digital shutter and two aqueous phases for hydrogel formation.
• Exploited liquid bridge dynamics at the liquid-liquid interface, toggling between maintenance and breakup to control shutter function.
• Modulated the digital shutter to control microfiber geometry (length, aspect ratio, curvature, torsion).

Main Results:

• Successfully fabricated hydrogel microfibers with diverse shapes, including linear, helical, tadpole-like, and spherical.
• Demonstrated high-resolution and high-viability cell-laden microfibers.
• Produced magnetically responsive microfibers, showcasing versatility.

Conclusions:

• The developed digital shutter mechanism provides precise, programmable control over hydrogel microfiber fabrication.
• The platform holds significant potential for applications in tissue engineering, active materials, and soft microrobotics.