Design and Fabrication of 3D printed Scaffolds with a Mechanical Strength Comparable to Cortical Bone to Repair Large Bone Defects.

Seyed-Iman Roohani-Esfahani,Peter Newman,Hala Zreiqat

doi:10.1038/srep19468

Seyed-Iman Roohani-Esfahani, Peter Newman + Show 1 more

Open Access

https://doi.org/10.1038/srep19468

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Journal: Scientific Reports	Publication Date: Jan 19, 2016
Citations: 275	License type: CC BY 4.0

Affiliation: University of Sydney

Abstract

A challenge in regenerating large bone defects under load is to create scaffolds with large and interconnected pores while providing a compressive strength comparable to cortical bone (100–150 MPa). Here we design a novel hexagonal architecture for a glass-ceramic scaffold to fabricate an anisotropic, highly porous three dimensional scaffolds with a compressive strength of 110 MPa. Scaffolds with hexagonal design demonstrated a high fatigue resistance (1,000,000 cycles at 1–10 MPa compressive cyclic load), failure reliability and flexural strength (30 MPa) compared with those for conventional architecture. The obtained strength is 150 times greater than values reported for polymeric and composite scaffolds and 5 times greater than reported values for ceramic and glass scaffolds at similar porosity. These scaffolds open avenues for treatment of load bearing bone defects in orthopaedic, dental and maxillofacial applications.

Highlights

A challenge in regenerating large bone defects under load is to create scaffolds with large and interconnected pores while providing a compressive strength comparable to cortical bone (100–150 MPa)
The ability of bone to self-repair after fracture is limited according to the extent of the damage; small fractures are usually able to heal perfectly, but larger fractures, known as segmental bone defects (SBDs), can leave permanent damage[1,2]
In order to meet these needs, the ideal scaffold requires porosity between 60% and 90% with an average pore size of > 150 μ m and compressive strength comparable to that of cortical bone, which is in the range of 100 to 150 MPa along the long axis[2,9,10]

Summary

Introduction

A challenge in regenerating large bone defects under load is to create scaffolds with large and interconnected pores while providing a compressive strength comparable to cortical bone (100–150 MPa). Baino et al fabricated a glass-ceramic scaffold to repair large defects in load-bearing bones by sponge template method[15] Their scaffold had a total porosity of 56% and the pore sizes ranged within 100–500 μ m. Huang et al introduced a motor assisted micro-syringe technique to fabricate HA/β -TCP scaffolds with homogeneous and interconnected pores in sizes ranging from 50 to 580 μ m They reported that average compressive strength of scaffolds with a porosity of ~50% reached 50.3 MPa after sintering in a microwave furnace[24]. The aim of this study was to utilise a direct ink writing method to fabricate glass-ceramic scaffolds with anisotropic structure and distinct pore geometry with required porosity and sufficient mechanical strength for treatment of bone defects under load. We designed a scaffold with hexagonal pore geometry to achieve a higher contact area between printed layers, producing a highly anisotropic scaffold architecture leading to enhanced load transfer compared other conventional patterns (rectangular, curved and zigzag)(Fig. 1)

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