Imaging Oxygen Concentrations in Bone Scaffolds during Cellular Activity and Fluid Perfusion.

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Tissue Engineering

Background:

• Developing large bone replacement scaffolds (>5 mm) is crucial for clinical applications in regenerative medicine.
• Oxygenating large scaffolds is challenging due to slow diffusion, leading to core necrosis.
• Current methods struggle to adequately supply oxygen to the interior of large scaffolds.

Purpose of the Study:

• To investigate methods for modulating and imaging oxygen concentration within large bone scaffolds.
• To assess the effectiveness of external perfusion in overcoming oxygen diffusion limitations.
• To establish a reproducible system for oxygenating tissue engineering scaffolds.

Main Methods:

• Utilized a flow chamber with an external perfusion pump to supply fresh medium to large scaffolds.
• Employed oxygen imaging techniques to monitor oxygen concentration below the scaffolds.
• Used yeast cells within the scaffold to simulate oxygen consumption and diffusion dynamics.
• Modulated oxygen levels by cycling perfusion on and off.

Main Results:

• Without external flow, yeast depleted oxygen, particularly in the scaffold center, consistent with reaction-diffusion models.
• Perfusion pumping restored oxygen levels within the scaffold.
• Oxygen profiles demonstrated high reproducibility across multiple perfusion cycles.
• The system successfully modulated and imaged oxygen gradients within the scaffold.

Conclusions:

• External perfusion is an effective strategy for oxygenating large bone scaffolds.
• This technique can prevent necrotic regions in the core of large scaffolds.
• The developed system provides a foundation for future in vivo studies on scaffold oxygenation.
• Advancements in scaffold oxygenation are critical for successful bone tissue engineering.