Osteogenic Activity on NaOH-Etched Three-Dimensional-Printed Poly-ɛ-Caprolactone Scaffolds in Perfusion or Spinner...

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Biomedical Engineering

Background:

• Bioreactor systems and 3D-printed scaffolds are crucial for bone tissue engineering, aiming to stimulate cells for bone graft production.
• Challenges remain in creating functional bone grafts using cell-seeded scaffolds within bioreactors due to critical parameters like fluid shear stress.
• Understanding how bioreactor parameters influence cell function on 3D-printed scaffolds is essential for clinical success.

Purpose of the Study:

• To compare the effects of spinner flask and perfusion bioreactors on the osteogenic responsiveness of pre-osteoblasts cultured on surface-modified 3D-printed poly-ɛ-caprolactone (PCL) scaffolds.
• To quantify wall shear stress (WSS) distribution and magnitude within scaffolds using finite element (FE)-modeling and experimental validation.
• To assess the impact of fluid shear stress on cell behavior, including spreading, proliferation, collagen, and calcium deposition.

Main Methods:

• Fabrication of surface-modified 3D-printed PCL scaffolds and customized static, spinner flask, and perfusion bioreactors.
• Utilized FE-modeling to simulate and quantify WSS distribution within scaffolds under different bioreactor conditions.
• Cultured MC3T3-E1 pre-osteoblasts on scaffolds for 7 days, followed by experimental assessment of scaffold properties and cell function.

Main Results:

• FE-modeling revealed differential WSS distribution, with perfusion bioreactors providing more homogeneous WSS compared to spinner flasks.
• Surface modification of PCL scaffolds with NaOH enhanced surface roughness and altered wettability.
• Both bioreactor types improved cell spreading, proliferation, and distribution; however, perfusion bioreactors significantly enhanced collagen and calcium deposition compared to static conditions.

Conclusions:

• Perfusion bioreactors offer a more advantageous environment for osteogenic differentiation of pre-osteoblasts on 3D-printed scaffolds due to more uniform mechanical stimulation.
• Accurate FE-modeling is vital for estimating WSS and optimizing experimental conditions in the design of cell-seeded scaffolds for bone tissue engineering.
• The findings provide critical insights for developing clinically relevant bone grafts using advanced bioreactor and scaffold technologies.