Mild formation of core-shell hydrogel microcapsules for cell encapsulation.

Area of Science:

• Biomaterials Science
• Chemical Engineering
• Regenerative Medicine

Background:

• Internal gelation is a key sol-gel method for microgel preparation, but often yields microgels with poor mechanical stability and low cell viability.
• Existing methods struggle with irregular surface morphology and insufficient cell survival rates, limiting applications in drug delivery and cell therapy.

Purpose of the Study:

• To develop an improved internal gelation approach for producing core-shell hydrogel microcapsules with enhanced mechanical stability, smooth surfaces, and high cell survival rates.
• To create microcapsules suitable for advanced applications like drug delivery, cell therapy, and tissue regeneration.

Main Methods:

• Utilized a coaxial flow-focusing microfluidic device for precise control over microcapsule formation.
• Employed alginate for the hydrogel shell, leveraging its rapid gelling properties for well-defined structures.
• Incorporated 2-[4-(2-Hydroxyethyl)piperazin-1-yl]ethanesulfonic acid (HEPES) in the shell stream to buffer acidity during crosslinking, ensuring cell viability.

Main Results:

• Successfully prepared core-shell hydrogel microcapsules (200-600 μm) with smooth surfaces and significantly improved mechanical stability.
• Achieved high cell survival rates for encapsulated HepG2 cells and 3T3 fibroblasts in a co-culture setting.
• Demonstrated that the mild gelation conditions preserve cell viability and functionality.

Conclusions:

• The enhanced internal gelation method offers a robust platform for generating high-quality hydrogel microcapsules.
• This technique overcomes limitations of previous methods, enabling effective cell encapsulation and supporting applications in regenerative medicine and drug delivery.
• The developed microcapsules show promise for advanced biomedical applications requiring stable, biocompatible structures.