Silk Fibroin Biomimetic Membranes with Villus-Crypt Architecture for In Vitro Intestinal Epithelium Modeling.

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Cell Biology

Background:

• Current 3D intestinal models lack native villus-crypt topography and crucial material cues.
• Physiologically relevant microarchitectures and mechanical support are essential for accurate epithelial behavior replication in vitro.

Purpose of the Study:

• To develop biomimetic silk fibroin (SF) membranes with native villus-crypt topography and tunable mechanical properties.
• To investigate the influence of matrix stiffness and β-sheet content on Caco-2 cell behavior.

Main Methods:

• Fabrication of SF membranes using chemical cross-linking (BDDE) for hydrogels and ethanol-induced β-sheet formation for stiff membranes.
• Replication of villus-crypt architectures using customized molds.
• Culturing Caco-2 cells on patterned SF membranes with varying stiffness and β-sheet content.

Main Results:

• SF membranes successfully reproduced villus-crypt topography with high fidelity.
• Physically cross-linked SF membranes (∼20 MPa) promoted robust epithelial cell adhesion, spreading, and differentiation (high ALP activity).
• Softer SF hydrogels (∼15 kPa) limited cell adhesion and proliferation.

Conclusions:

• A tunable SF-based platform was established, providing both physiological topography and mechanical support for intestinal models.
• This platform offers a promising foundation for developing advanced 3D in vitro intestinal epithelial models.
• The study highlights the importance of matrix mechanics and structure in guiding epithelial organization.