Molding of hydrogel microstructures to create multiphenotype cell microarrays.

Area of Science:

• Biomaterials Engineering
• Tissue Engineering
• Microfluidics

Background:

• Fabricating controlled 3D microenvironments for mammalian cells is crucial for tissue engineering and biosensing applications.
• Existing methods often face challenges in achieving uniform cell distribution and long-term cell viability within microstructures.

Purpose of the Study:

• To develop a method for fabricating mammalian cell-containing poly(ethylene glycol) (PEG) hydrogel microstructures.
• To investigate the impact of Arg-Gly-Asp (RGD) peptide modification on cell behavior within the hydrogels.
• To explore the potential for creating multiphenotype cell-based biosensors using these microstructures.

Main Methods:

• Utilized photoreaction injection molding within poly(dimethylsiloxane) microfluidic channels to create 3D hydrogel microstructures.
• Encapsulated various mammalian cells, including fibroblasts, hepatocytes, and macrophages, ensuring uniform distribution.
• Modified PEG hydrogels with Arg-Gly-Asp (RGD) peptide sequences to promote cell adhesion and spreading.

Main Results:

• Achieved uniform cell distribution and controlled cell numbers within individual hydrogel microstructures by adjusting precursor solution cell density.
• Demonstrated enhanced fibroblast spreading over 24 hours due to RGD incorporation.
• Maintained high cell viability for over one week in culture.
• Successfully fabricated arrays of microstructures with multiple cell phenotypes on a single substrate.

Conclusions:

• The developed photoreaction injection molding technique enables the precise fabrication of cell-laden PEG hydrogel microstructures.
• RGD modification significantly improves cell-material interactions, promoting cell spreading and viability.
• The ability to create multiphenotype microstructures holds promise for the development of novel cell-based biosensors.