A comparative analysis of scaffold material modifications for load-bearing applications in bone tissue engineering

doi:10.1016/j.ijom.2006.03.024

International Journal of Oral and Maxillofacial Surgery

Volume 35, Issue 10, October 2006, Pages 928-934

https://doi.org/10.1016/j.ijom.2006.03.024 Get rights and content

Abstract

To facilitate optimal application of appropriate scaffold architectures for clinical trials, there is a need to compare different scaffold modifications under similar experimental conditions. In this study was assessed the effectiveness of poly-e-caprolactone (PCL) scaffolds fabricated by fused deposition modelling (FDM), with varying material modifications, for the purposes of bone tissue engineering. The incorporation of hydroxyapatite (HA) in PCL scaffolds, as well as precalcification through immersion in a simulated body fluid (SBF) to produce a biomimetic apatite coating on the scaffolds, was assessed. A series of in vitro studies spanning 3 weeks as well as in vivo studies utilizing a subcutaneous nude mouse model were carried out. PCL and HA–PCL scaffolds demonstrated increasing tissue growth extending throughout the implants, as well as superior mechanical strength and mineralization, as evidenced by X-ray imaging after 14 weeks in vivo. No significant difference was found between PCL and HA–PCL scaffolds. Precalcification with SBF did not result in increased osteoconductivity and cell proliferation as previously reported. Conversely, tensile forces exerted by tissue sheets bridging adjacent struts of the PCL scaffold caused flaking of the apatite coating that resulted in impaired cell attachment, growth and mineralization. The results suggest that scaffolds fabricated by FDM may have load-bearing applications.

Section snippets

Fabrication of scaffolds by fused deposition modelling

PCL scaffolds were fabricated by FDM as previously described by Hutmacher et al.⁶ For HA–PCL scaffolds, PCL powder (catalog no. 44, 074-4, Aldrich Chemical Co., Milwaukee, WI, USA), Mn of approximately 80,000 Da (gel permeation chromography) and melt index of 1.0 g/10 min (125 °C/44 psi ASTM D1238-73), and HA (microemulsion-derived CaPO₄ powder) were dried separately for 24 h in a vacuum oven at 120 and 40 °C, respectively. Composite pellets of PCL–HA were then formed by casting a solvent mixture of 20

Cell growth and differentiation in vitro

Calvarial osteoblasts were successfully isolated and seeded onto the 3 different groups of polymer scaffolds, after initial expansion in 2-dimensional culture for 2 weeks. When seeded onto all 3 types of scaffold, cells attached, spread and proliferated, adopting a stellate morphology typical of attached cells, with numerous filopodia and cell-to-cell contacts visible. The PCL FDM and HA–PCL FDM scaffolds demonstrated a constant rate of cell proliferation, with cells initially attaching to the

Discussion

For tissue-engineering strategies to progress to clinic trials, adequate studies must be performed to compare different scaffold modifications and cells under similar experimental conditions. Here, it was sought to compare different modifications on a scaffold designed for load-bearing applications in bone tissue engineering. Scaffolds fabricated by FDM have adequate mechanical strength, and allow ingrowth of tissue throughout the implant, as demonstrated. The fabrication process allows

Acknowledgement

Authors would like to thank Ms Gouk Sok Siam for much invaluable assistance with this project.

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Citation Excerpt :
However, highly porous scaffolds can be fabricated, in which the porosity influences the resorption rate of the materials [133]. Scaffolds fabricated by FDM have found load-bearing applications [51]. However, the disadvantage of using FDM for scaffold printing is the limited shape of the scaffold that can be produced because of the poor resolution of the technique compared with SLA [134].

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^☆: Presented in part at the First Biennial Meeting of the European Tissue Engineering Society (ETES) in November 2001.

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Leading Research PaperTissue EngineeringA comparative analysis of scaffold material modifications for load-bearing applications in bone tissue engineering☆

Abstract

Section snippets

Fabrication of scaffolds by fused deposition modelling

Cell growth and differentiation in vitro

Discussion

Acknowledgement

Biomaterials

Biomaterials

Biomaterials

Biomaterials

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J Cell Physiol

In vitro evaluation of novel bioactive composites based on Bioglass-filled polylactide foams for bone tissue engineering scaffolds

J Biomed Mater Res

In vitro bioactivity of S520 glass fibers and initial assessment of osteoblast attachment

J Biomed Mater Res A

Osteogenic induction of human bone marrow-derived mesenchymal progenitor cells in novel synthetic polymer–hydrogel matrices

Tissue Eng

Use of a biomimetic strategy to engineer bone

J Biomed Mater Res

Mechanical properties and cell cultural response of polycaprolactone scaffolds designed and fabricated via fused deposition modeling

J Biomed Mater Res

Bone formation by three-dimensional stromal osteoblast culture in biodegradable polymer scaffolds

J Biomed Mater Res

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Science

Tissue engineered bone-regeneration using degradable polymers: the formation of mineralized matrices

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Leading Research Paper
Tissue Engineering
A comparative analysis of scaffold material modifications for load-bearing applications in bone tissue engineering☆