Guidance of engineered tissue collagen orientation by large-scale scaffold microstructures

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Biomechanical Engineering

Background:

• Collagen fiber orientation dictates soft tissue strength and stiffness.
• Microgrooved substrates orient cells and collagen in 2D cultures.
• 3D tissue engineering scaffolds have unique pore networks influencing cell and collagen behavior.

Purpose of the Study:

• Quantify the capacity of large, geometrically defined open pores to guide cell and collagen orientation in engineered tissues.
• Investigate the influence of pore geometry, specifically aspect ratio, on cellular and matrix alignment within 3D scaffolds.

Main Methods:

• Fabricated epoxy resin scaffolds with rectangular pores (200 micrometers wide, aspect ratios 1:1 to 10:1) using stereolithography.
• Surface modified scaffolds with GRGDS peptides for cell adhesion.
• Seeded scaffolds with neonatal rat skin fibroblasts and incubated for 4 weeks.
• Assessed collagen orientation via small angle light scattering (SALS) and cell orientation via confocal and scanning electron microscopy.

Main Results:

• Cells aligned circumferentially within pores and along strut axes.
• Pore aspect ratio significantly influenced cell and collagen orientation; higher ratios promoted alignment.
• Alignment increased parallel to the long strut axis with increasing pore aspect ratio.
• Pore shape (rectangular vs. diamond) impacts sensitivity to initial cell seeding conditions.

Conclusions:

• Geometrically defined, high aspect ratio pores in 3D scaffolds can effectively guide cell and collagen orientation.
• Pore geometry is a critical factor in controlling tissue development and mechanical properties in tissue engineering.
• Diamond-shaped pores may offer more consistent orientation guidance due to reduced sensitivity to initial cell attachment patterns.