Granular, hierarchically porous polymer scaffolds for bone tissue engineering.

Area of Science:

• Biomaterials Science
• Orthopedic Engineering
• Regenerative Medicine

Background:

• Bone defects present significant clinical challenges due to limitations in current implant durability, integration, and infection risk.
• Existing bulk scaffolds fail to conform to irregular defect shapes, hindering effective treatment.
• Novel therapeutic strategies are essential for managing critical-size bone defects.

Purpose of the Study:

• To develop and evaluate novel granular scaffolds for bone defect regeneration.
• To create hierarchically porous scaffolds with defined internal channels capable of conforming to complex defect morphologies.
• To assess the physical properties and biological performance of these granular scaffolds.

Main Methods:

• Granular, hierarchically porous, emulsion-templated (polyHIPE) scaffolds were fabricated using UV-initiated photopolymerization of specific monomers.
• 3D-printed, water-soluble poly(vinyl alcohol) (PVA) lattices were incorporated to create 500 µm channels within the granules.
• Scaffold morphology, porosity, density, and cell behavior (proliferation, infiltration) were analyzed using SEM, mercury intrusion porosimetry, helium pycnometry, and cell culture assays in a bioreactor.

Main Results:

• Channeled polyHIPE granules exhibited larger void diameters (24.3 ± 1.4 µm) compared to non-channeled ones (18.2 ± 1.1 µm).
• Scaffolds demonstrated high porosity (>80%), interconnected pores (3-4 µm), and suitable skeletal density (1.4 g cm⁻³).
• Biological evaluations confirmed comparable MG63 osteosarcoma cell proliferation and infiltration on channeled granules within a bioreactor system.

Conclusions:

• The developed 500 µm polyHIPE granular scaffolds, combined with optimized bioreactor systems, provide a promising platform for bone regeneration.
• These conformable scaffolds can address complex and irregular bone defects, facilitating minimally invasive procedures.
• This approach offers a potential advancement in orthopedic and reconstructive surgery for bone defect management.