Structural Evolution of an Optimized Highly Interconnected Hierarchical Porous Mg Scaffold under Dynamic Flow...

Area of Science:

• Biomaterials Science
• Orthopedic Engineering
• Tissue Engineering

Background:

• Magnesium (Mg) and its alloys are promising for bone screws due to biocompatibility and biodegradability.
• Controlled Mg2+ ion release aids bone fracture healing, making Mg attractive for tissue engineering.
• Porous Mg scaffolds offer high surface area but struggle with slow degradation and maintaining interconnectivity for tissue ingrowth.

Purpose of the Study:

• To introduce a highly interconnected hierarchical porous Mg scaffold.
• To investigate scaffold degradation behavior under simulated body fluid flow rates.
• To elucidate how degradation impacts scaffold interconnectivity and structural integrity.

Main Methods:

• Utilized a bioreactor to simulate in vivo degradation conditions with varying body fluid flow rates.
• Analyzed the evolution of the porous structure and scaffold interconnectivity over 42 days.
• Quantified porosity changes and deposit formation at different flow rates (0.5, 1.0, 2.0 mL/min).

Main Results:

• Initial scaffold interconnectivity is significantly influenced by fluid flow rate.
• Lower flow rates (0.5 mL/min) led to substantial Mg2+ ion accumulation and pore occlusion by deposits.
• Porosity decreased significantly: 41.25% at 0.5 mL/min, 58.52% at 1.0 mL/min, and 68.80% at 2.0 mL/min after 42 days.
• Reduced porosity and pore space occlusion hindered scaffold interconnectivity.

Conclusions:

• Fluid flow rate is a critical factor in managing Mg scaffold degradation and maintaining structural integrity.
• The degree of porosity reduction can serve as an indicator for assessing a scaffold's ability to retain interconnectivity.
• Findings offer insights into designing Mg scaffolds with optimized pore strut and interconnectivity for enhanced tissue engineering applications.