In vivo bone regeneration assessment of offset and gradient melt electrowritten (MEW) PCL scaffolds
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RESEARCH ARTICLE
Open Access
In vivo bone regeneration assessment of offset and gradient melt electrowritten (MEW) PCL scaffolds Naghmeh Abbasi1,2* , Ryan S. B. Lee1,3, Saso Ivanovski3, Robert M. Love1 and Stephen Hamlet1,2*
Abstract Background: Biomaterial-based bone tissue engineering represents a promising solution to overcome reduced residual bone volume. It has been previously demonstrated that gradient and offset architectures of threedimensional melt electrowritten poly-caprolactone (PCL) scaffolds could successfully direct osteoblast cells differentiation toward an osteogenic lineage, resulting in mineralization. The aim of this study was therefore to evaluate the in vivo osteoconductive capacity of PCL scaffolds with these different architectures. Methods: Five different calcium phosphate (CaP) coated melt electrowritten PCL pore sized scaffolds: 250 μm and 500 μm, 500 μm with 50% fibre offset (offset.50.50), tri layer gradient 250–500-750 μm (grad.250top) and 750–500-250 μm (grad.750top) were implanted into rodent critical-sized calvarial defects. Empty defects were used as a control. After 4 and 8 weeks of healing, the new bone was assessed by micro-computed tomography and immunohistochemistry. Results: Significantly more newly formed bone was shown in the grad.250top scaffold 8 weeks postimplantation. Histological investigation also showed that soft tissue was replaced with newly formed bone and fully covered the grad.250top scaffold. While, the bone healing did not happen completely in the 250 μm, offset.50.50 scaffolds and blank calvaria defects following 8 weeks of implantation. Immunohistochemical analysis showed the expression of osteogenic markers was present in all scaffold groups at both time points. The mineralization marker Osteocalcin was detected with the highest intensity in the grad.250top and 500 μm scaffolds. Moreover, the expression of the endothelial markers showed that robust angiogenesis was involved in the repair process. Conclusions: These results suggest that the gradient pore size structure provides superior conditions for bone regeneration. Keywords: Pore size, Melt electrowriting, Bone tissue engineering, Angiogenesis, Scaffold, Poly (ε-caprolactone)
* Correspondence: [email protected]; [email protected]; [email protected] 1 School of Dentistry and Oral Health, Griffith University, Gold Coast Campus, Southport, Queensland 4215, Australia Full list of author information is available at the end of the article © The Author(s). 2020 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the materia