Droplet-Based Microfluidic Preparation of Shape-Variable Alginate Hydrogel Magnetic Micromotors

Area of Science:

• Materials Science
• Biomedical Engineering
• Microfluidics

Background:

• Microfluidic devices offer precise control over particle synthesis.
• Magnetic hydrogel micromotors show promise for targeted delivery applications.
• Controlling micromotor shape and locomotion is crucial for their functionality.

Purpose of the Study:

• To introduce a facile droplet-based microfluidic method for preparing Fe3O4-incorporated alginate hydrogel magnetic micromotors.
• To investigate the effect of fabrication parameters on micromotor shape and size.
• To demonstrate the magnetic field-actuated locomotion of these micromotors.

Main Methods:

• Utilized droplet-based microfluidics and water diffusion for synthesizing sodium alginate and Fe3O4 microparticles.
• Employed calcium chloride (CaCl2) for gelation, forming calcium alginate hydrogel microparticles.
• Investigated locomotion under rotating and gradient magnetic fields.

Main Results:

• Achieved monodisperse (quasi-)spherical Na-Alg/Fe3O4 microparticles with diameters ranging from 31.9 to 102.7 µm.
• Fabricated spherical, droplet-like, and worm-like Ca-Alg/Fe3O4 micromotors by varying CaCl2 concentration.
• Demonstrated magnetic field-controlled locomotion with spherical micromotors reaching velocities up to 158.2 µm/s.

Conclusions:

• The developed microfluidic method is efficient for producing shape-variable magnetic hydrogel micromotors.
• The method avoids complex patterning or sophisticated equipment, making it accessible.
• These micromotors hold significant potential for biomedical applications, particularly in targeted drug delivery.