4D anisotropic skeletal muscle tissue constructs fabricated by staircase effect strategy

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Cellular Biology

Background:

• Unidirectional anisotropic scaffolds are crucial for guiding cell behavior in anisotropic tissue engineering, mimicking native tissue structures like skeletal muscle.
• Fused deposition modeling (FDM) typically produces contour-like staircases, often viewed as a defect, which possess inherent directional topographical cues.

Purpose of the Study:

• To leverage the staircase defect of FDM by integrating it with a surface coating technique (FCT) to create effective bioengineering strategies.
• To investigate the impact of topographical cues on regulating human mesenchymal stem cell (hMSC) behavior for skeletal muscle tissue development.
• To fabricate shape-specific, multi-dimensional anisotropic scaffolds using various biomaterials.

Main Methods:

• Developed 2D anisotropic scaffolds using different polycaprolactone concentrations to direct hMSC alignment.
• Created 3D anisotropic scaffolds with thin wall features by surface coating FDM-printed sacrificial structures, regulating seeded hMSCs via a rotating bioreactor.
• Utilized layer-by-layer coating with a shape memory polymer to create 4D smart constructs with shape fix and recovery capabilities.

Main Results:

• Demonstrated efficient hMSC alignment on 2D anisotropic scaffolds, particularly when immobilized on a support ring.
• Confirmed that topographical cues generated via FCT significantly enhance the expression of myogenic genes (myoblast differentiation protein-1, desmin, myosin heavy chain-2) in hMSCs.
• Successfully fabricated advanced 3D and 4D anisotropic scaffolds with tunable properties for cell regulation.

Conclusions:

• The integration of FDM with FCT effectively translates a printing defect into a valuable bioengineering strategy for creating anisotropic scaffolds.
• Topographical cues play a significant role in directing hMSC differentiation towards skeletal muscle lineages.
• This FCT strategy holds broad potential for tissue engineering applications, especially for tissues with highly organized, anisotropic extracellular matrix components like skeletal muscle.