Speaker
Description
Introduction
Melt-electrowriting (MEW) is an additive manufacturing technology with the potential to produce regenerative scaffolds that replicate key aspects of the hierarchical structure of musculoskeletal tissues. As small scale polymeric fibres can be accurately deposited using MEW, highly porous 3D scaffolds with well-defined and repeatable pore dimensions can be produced. Herein, we describe the development of biphasic MEW scaffolds with regionally distinct compositions and pore sizes to facilitate the regeneration of osteochondral defects in vivo.
Materials and Methods
The bone phase of the scaffolds consisted of square pores measuring 600 µm with fibres of 18 µm in diameter, while the cartilage phase also consisted of 600 µm pores but with thinner fibres measuring 10 µm in diameter. The MEW scaffold was then placed into a fused deposition modelling (FDM) fabricated tubular structure of 5.85 mm outer diameter, 0.5 mm wall thickness, and 4 mm tall. Slots in the tube wall were designed to catch on the MEW fibres and fix the MEW scaffold in the FDM shell, similar to a previous osteoinductive scaffold [1]. The bone phase of the scaffolds were coated in nano-needle hydroxyapatite (nnHA) which served purpose of double purpose of promoting osteogenesis and consolidating the hybrid structure. The scaffolds were then implanted in a defect made in the trochlear groove of 7 Saanen female goats, and histological analysis was performed after 6 months.
Results
No adverse events were experienced as a result of the surgery or scaffold implantation over the 6 months. The presence of the MEW scaffold enhanced new bone formation and cartilage integration. Histological quantification revealed that the presence of the hybrid scaffold led to significantly more bone formation than the empty control; 40.2% ± 12.9% new bone tissue compared to 22.2% ± 13.1%, respectively. Newly formed cartilage in the defect site stained positively for collagen type II, while newly formed bone tissue stained positively for collagens type I and X.
Discussion
This hybrid MEW-FDM strategy demonstrates the capacity to guide osteochondral repair through biomimetic architectural design. The MEW scaffold promotes targeted tissue integration, while the FDM shell supports surgical handling. However, limited porosity in the FDM component may hinder full tissue infiltration, suggesting future improvements could include increased shell porosity and incorporation of additional scaffold phases to better replicate the osteochondral interface.
Conclusion
These findings highlight the potential of hierarchical MEW-FDM scaffolds as a platform for osteochondral regeneration, and support further optimization of scaffold architecture to enhance integration and long-term functional repair.
[1] K. F. Eichholz, P. Pitacco, R. Burdis, F. Chariyev-Prinz, X. Barceló, B. Tornifoglio, R. Paetzold, O. Garcia, D. J. Kelly, Adv. Healthc. Mater. 2023, 2302057, 1.
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