Three-dimensional heterogeneous assembly of coded microgels using an untethered mobile microgripper

Area of Science:

• Robotics
• Materials Science
• Microfluidics

Background:

• 3D microgel assembly is crucial for creating complex microsystems.
• Existing methods face limitations in layer control and construct stability.

Purpose of the Study:

• To demonstrate a novel microrobotic system for precise 3D heterogeneous assembly of coded microgels.
• To overcome limitations in microgel assembly layer count and post-assembly fixation.

Main Methods:

• Utilized a remotely actuated magnetic micro-gripper controlled by an electromagnetic coil system.
• Employed 'stick-slip' and 'rolling' locomotion for 2D movement and magnetic gradient-based pulling force for 3D levitation.
• Assembled coded microgels (varying colors and shapes) onto prefabricated microposts.

Main Results:

• Achieved precise manipulation and orientation control of individual microgels in all x-y-z directions.
• Demonstrated the assembly of up to ten layers of microgels on a single micropost.
• Successfully constructed complex heterogeneous microsystems by varying micropost number and distribution.

Conclusions:

• The developed microrobotic assembly method enables unprecedented control over 3D microgel arrangements.
• The technique eliminates the need for secondary cross-linking, simplifying construct fabrication.
• This advancement paves the way for creating sophisticated 3D micro-devices and integrated microsystems.