Quantitative analysis of three-dimensional fluid flow in rotating bioreactors for tissue engineering

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Bioreactor Technology

Background:

• Organ and tissue shortages necessitate alternatives like tissue engineering.
• Previous work developed sintered spherical particle matrices for bone tissue engineering.
• Bioreactor technology enables in vitro production of highly mineralized matrices.

Purpose of the Study:

• To develop porous microcapsule scaffolds for bone tissue engineering.
• To analyze microcapsule and scaffold motion within a high aspect ratio vessel rotating bioreactor.
• To evaluate fluid dynamics and shear stress within the scaffolds for optimized tissue synthesis.

Main Methods:

• Fabrication of lighter-than-water scaffolds using sintered poly(lactic-co-glycolic acid) hollow microcarriers.
• Numerical simulation and in situ imaging to study microcapsule and scaffold dynamics.
• Calculation of scaffold velocity, external/internal shear stress, and internal perfusion velocity.

Main Results:

• Spherical microcapsules exhibited circular orbits and inward radial migration.
• Scaffolds with densities from 0.65-0.99 g/mL were fabricated with ~30% pore volume.
• Predicted scaffold velocities ranged from 100 mm/s to 3 mm/s, with shear stresses from 0.3 N/m² to 0.0007 N/m².

Conclusions:

• Porous microcapsule scaffolds are viable for bone tissue engineering.
• Analytical methods accurately predict scaffold behavior and fluid dynamics in bioreactors.
• This approach facilitates the study of bone tissue synthesis in 3D culture with fluid flow.