Poster Presentation ESA-SRB-ANZBMS 2024 in conjunction with ENSA

Convergence of 3D Printing, Scaffoldomics and Bone Regeneration – Designing New Toughened Biodegradable Composites with Weak Interfaces (#330)

sacha cavelier 1 2 3 , Dietmar W Hutmacher 1 2 3
  1. School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, QLD, Australia
  2. Max Planck Queensland Centre for the Materials Science of Extracellular Matrices, Queensland University of Technology, Brisbane, QLD, Australia
  3. ARC Training Centre for Cell and Tissue Engineering Technologies, Queensland University of Technology, Brisbane, QLD, Australia

Scaffold guided bone regeneration (SGBR) is a rapidly developing field that aims to address the clinical challenges in reconstructive surgery. Combining the variety of ceramics with certain polymers offers a wide range of physico-chemical properties crucial for SGBR, such as osteoconductivity or tuneable biodegradability [1]. However, these materials usually exhibit a lack of mechanical properties. By increasing their ceramic content, the strength and toughness can be improved but this strategy is usually detrimental for the toughness [2]. However, Nature offers examples of highly mineralized biological materials, such as nacre, teeth, or natural bone, with excellent mechanical properties [3]. This can be attributed to their unique architecture featuring soft polymeric interfaces that are capable of deflecting propagating cracks. These toughening mechanisms dissipate energy, and the overall toughness of the material is increased by several orders of magnitude [4,5,6]. It is crucial to replicate these mechanisms experimentally to design superior biocomposites.

Aim: This prospective work aims to guide biomedical engineers in the field of bone tissue engineering to design the future of bone graft materials.

Methods: The present work reminds the exceptional structure of natural bone, and the role of soft interfaces on its toughness. Then, a thorough exploration of the literature on fracture mechanics, crack propagation models and example of toughened ceramics is presented [4,5,6]. Ultimately, the work depicts toughening mechanisms and governing equations applied to a crack propagating in bone interfaces [7,8].

Results: From these equations are derived criteria and guidelines for the design of bone graft materials, combining superior mechanical properties and high ceramic content. Interfaces at least four times tougher than the ceramic matrix optimize crack deflection and overall mechanical properties, but also a high number of layers and thinner interfaces.

Conclusion: Bone graft materials with superior mechanical properties can be achieved with simple but controlled architectures.

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