Abstract
Biomaterial bone scaffolds offer a promising alternative to traditional treatments. Bioactive glass has shown promise however its clinical application is limited by its poor mechanical properties. Flexible hybrids are a potential solution. Herein, previous studies incorporated calcium into a silica/poly(tetrahydrofuran)/poly(ε-caprolactone) (SiO₂/PTHF/PCL-diCOOH) sol-gel hybrid to enhance its mechanical performance. We firstly compared these material scaffolds to 13–93 bioactive glass (13–93 BG) (54.6% SiO2, 22.1% CaO, 6.0% Na2O, 7.7% MgO, 7.9% K2O, and 1.7% P2O5, in mol%) scaffolds. We reveal that the hybrid material exhibits a randomised porous microstructure and superior mechanical deformability, whereas the 13–93 BG scaffolds remain stiffer and more brittle. Micro-computed tomography (µCT) quantification reveals that the glass scaffolds underwent less shrinkage after direct ink writing (DIW) than the hybrid scaffolds, enabling easier reproduction of the design files. We demonstrate that the hybrid scaffold can withstand strains of up to 7%, mimicking the elastic behaviour of bone, while the 13–93 BG scaffold fails at 2% strain. Finite element (FE) analysis revealed a more decentralized stress distribution and higher local strain within the hybrid scaffold, whereas the 13–93 BG scaffold showed high stress concentration at strut junctions in line with a higher risk of brittle failure. The characterisation methods applied in this study can be extended to other biomaterials, providing valuable insights for biomaterials research and guiding scaffold design for bone regeneration.
Data availability
All data supporting the findings of this study are available within the paper and its supplementary information.
References
Shi, X. et al. Bioactive glass scaffold architectures regulate patterning of bone regeneration in vivo. Appl. Mater. Today. 20, 100770 (2020).
de Fernandez, G. et al. Bone substitutes: A review of their characteristics, clinical use, and perspectives for large bone defects management. J. Tissue Eng. 9, 2041731418776819 (2018).
Stahl, A. & Yang, Y. P. Regenerative approaches for the treatment of large bone defects. Tissue Eng. Part. B: Rev. 27, 539–547 (2021).
Chung, J. J. et al. 3D printed porous methacrylate/silica hybrid scaffold for bone substitution. Adv. Healthc. Mater. 10, 2100117 (2021).
Miller, C. P. & Chiodo, C. P. Autologous bone graft in foot and ankle surgery. Foot Ankle Clin. 21, 825–837 (2016).
Dimitriou, R., Jones, E., McGonagle, D. & Giannoudis, P. V. Bone regeneration: Current concepts and future directions. BMC Med. 9, 66 (2011).
Hench, L. L. & Polak, J. M. Third-generation biomedical materials. Science 295, 1014–1017 (2002).
Jones, J. R. 12—Bioactive glass. In Bioceramics and Their Clinical Applications (ed. Kokubo, T.) 266–283 (Woodhead Publishing, 2008). https://doi.org/10.1533/9781845694227.2.266.
Massera, J., Mishra, A., Guastella, S., Ferraris, S. & Verné, E. Surface functionalization of phosphate-based bioactiveglasses with 3-aminopropyltriethoxysilane (APTS). Biomed. Glasses 2, 51–62 (2016).DOI:http://dx.doi.org/10.1515/bglass-2016-0007
Hench, L. L. & Jones, J. R. Bioactive glasses: Frontiers and challenges. Front. Bioeng. Biotechnol. 3, 194 (2015).
Ferraz, M. P. Bone grafts in dental medicine: An overview of autografts, allografts and synthetic materials. Materials 16, 4117 (2023).
Zhou, L. et al. Additive manufacturing: A comprehensive review. Sensors 24, 2668 (2024).
Baino, F. & Fiume, E. 3D printing of hierarchical scaffolds based on mesoporous bioactive glasses (MBGs)—Fundamentals and applications. Materials 13, 1688 (2020).
Distler, T. et al. Polymer-bioactive glass composite filaments for 3D scaffold manufacturing by fused deposition modeling: Fabrication and characterization. Front. Bioeng. Biotechnol. 8, 552. https://doi.org/10.3389/fbioe.2020.00552/full (2020).
Nommeots-Nomm, A., Lee, P. D. & Jones, J. R. Direct ink writing of highly bioactive glasses. J. Eur. Ceram. Soc. 38, 837–844 (2018).
Vidal, E. et al. Titanium scaffolds by direct ink writing: Fabrication and functionalization to guide osteoblast behavior. Metals 10, 1156 (2020).
Fu, Q., Saiz, E. & Tomsia, A. P. Direct ink writing of highly porous and strong glass scaffolds for load-bearing bone defects repair and regeneration. Acta Biomater. 7, 3547–3554 (2011).
Saadi, M. S. R. et al. Direct ink writing: A 3D printing technology for diverse materials. Adv. Mater. 34, 2108855 (2022).
Jones, J. R. Review of bioactive glass: From Hench to hybrids. Acta Biomater. 9, 4457–4486 (2013).
Liu, X., Rahaman, M. N., Hilmas, G. E. & Bal, B. S. Mechanical properties of bioactive glass (13–93) scaffolds fabricated by robotic deposition for structural bone repair. Acta Biomater. 9, 7025–7034 (2013).
Tallia, F. et al. Bouncing and 3D printable hybrids with self-healing properties. Mater. Horiz. 5, 849–860 (2018).
Li, S., Tallia, F., Mohammed, A. A., Stevens, M. M. & Jones, J. R. Scaffold channel size influences stem cell differentiation pathway in 3-D printed silica hybrid scaffolds for cartilage regeneration. Biomater. Sci. 8, 4458–4466 (2020).
Tallia, F. et al. Bioactive, degradable and tough hybrids through calcium and phosphate incorporation. Front. Mater. 9, 901196 (2022).
Heyraud, A. et al. Calcium sources can increase mechanical properties of 3D printed bioactive hybrid bone scaffolds. RSC Adv. 14, 37846–37858 (2024).
Heyraud, A. et al. 3D printed hybrid scaffolds for bone regeneration using calcium methoxyethoxide as a calcium source. Front. Bioeng. Biotechnol. 11, 1224596 (2023).
Shi, X. et al. Bioactive glass scaffold architectures regulate patterning of bone regeneration in vivo. Appl. Mater. Today. 20, 100770 (2020).
Gouveia, Z., Perinpanayagam, H. & Zhu, J. Development of multifunctional Si-Ca-PEG-nAg sol–gel implant coatings from calcium-2-ethoxyethoxide. J. Coat. Technol. Res. 18, 1177–1189 (2021).
Pickup, D. M. et al. Preparation, structural characterisation and antibacterial properties of Ga-doped sol–gel phosphate-based glass. J. Mater. Sci. 44, 1858–1867 (2009).
Heyraud, A. et al. 3D printed hybrid scaffolds for bone regeneration using calcium methoxyethoxide as a calcium source. Front. Bioeng. Biotechnol. 11, 1224596. https://doi.org/10.3389/fbioe.2023.1224596/full (2023).
Heyraud, A. et al. Calcium sources can increase mechanical properties of 3D printed bioactive hybrid bone scaffolds. RSC Adv. 14, 37846–37858 (2024).
Zhang, L. et al. The investigation of permeability calculation using digital core simulation technology. Energies 12, 3273 (2019).
Doube, M. et al. BoneJ: Free and extensible bone image analysis in ImageJ. Bone 47, 1076–1079 (2010).
Xiao, W., Zaeem, M. A., Bal, B. S. & Rahaman, M. N. Creation of bioactive glass (13–93) scaffolds for structural bone repair using a combined finite element modeling and rapid prototyping approach. Mater. Sci. Eng. C. 68, 651–662 (2016).
Hoppe, A. et al. Cobalt-releasing 1393 bioactive glass-derived scaffolds for bone tissue engineering applications. ACS Appl. Mater. Interfaces. 6, 2865–2877 (2014).
Gupta, N., Vyas, V. K. & Mandal, A. Studies of substitution effect of B2O3 on structure and properties of 1393 bioactive glass. Orient. J. Chem. 37, 1409–1414 (2021).
Yadav, S. K. et al. Development of zirconia substituted 1393 bioactive glass for orthopaedic application. Orient. J. Chem. 33, 2720–2730 (2017).
Liu, X., Rahaman, M. N., Hilmas, G. E. & Bal, B. S. Mechanical properties of bioactive glass (13–93) scaffolds fabricated by robotic deposition for structural bone repair. Acta Biomater. 9, 7025–7034 (2013).
Kaur, G. et al. Mechanical properties of bioactive glasses, ceramics, glass-ceramics and composites: State-of-the-art review and future challenges. Mater. Sci. Eng. C. 104, 109895 (2019).
Powell, D. R., Swarbrick, J. & Banker, G. S. Effects of shear processing and thermal exposure on the viscosity-stability of polymer solutions. J. Pharm. Sci. 55, 601–605 (1966).
Friedrich, L. & Begley, M. In situ characterization of low-viscosity direct ink writing: Stability, wetting, and rotational flows. J. Colloid Interface Sci. 529, 599–609 (2018).
Li, M. et al. Microstructure, mechanical properties, corrosion resistance and cytocompatibility of WE43 Mg alloy scaffolds fabricated by laser powder bed fusion for biomedical applications. Mater. Sci. Eng. C. 119, 111623 (2021).
Ciliveri, S. & Bandyopadhyay, A. Influence of strut-size and cell-size variations on porous Ti6Al4V coated structures for load-bearing implants. J. Mech. Behav. Biomed. Mater. 126, 105023 (2022).
Mour, M. et al. Advances in porous biomaterials for dental and orthopaedic applications. Materials 3(5), 2947–2974 (2010).
Mukasheva, F. et al. Optimizing scaffold pore size for tissue engineering: Insights across various tissue types. Front. Bioeng. Biotechnol. 12, 1444986 (2024).
Pountos, I., Panteli, M., Panagiotopoulos, E., Jones, E. & Giannoudis, P. V. Can we enhance fracture vascularity: What is the evidence? Injury 45, S49–S57 (2014).
Lim, T. C., Chian, K. S. & Leong, K. F. Cryogenic prototyping of chitosan scaffolds with controlled micro and macro architecture and their effect on in vivo neo-vascularization and cellular infiltration. J. Biomedical Mater. Res. Part. A. 94A, 1303–1311 (2010).
Dorozhkin, S. V. Calcium orthophosphate-based bioceramics. Materials (Basel). 6, 3840–3942 (2013).
Gleeson, J. P., Plunkett, N. A. & O’Brien, F. J. Addition of hydroxyapatite improves stiffness, interconnectivity and osteogenic potential of a highly porous collagen-based scaffold for bone tissue regeneration. Eur. Cell. Mater. 20, 218–230 (2010).
Yushchenko, V. S., Shchukin, E. D. & Hotokka, M. Ab initio calculation of the mechanical strength of the Si-O-Si bond. J. Mater. Sci. 29, 3038–3042 (1994).
Simmons, J. H., Swiler, T. P. & Ochoa, R. Molecular dynamics studies of brittle failure in silica: Bond fracture. J. Non-cryst. Solids. 134, 179–182 (1991).
Gibson, L. J. & Ashby, M. F. Cellular Solids: Structure and Properties (Cambridge University Press, 1997). https://doi.org/10.1017/CBO9781139878326
Turunen, M. J. et al. Sub-trabecular strain evolution in human trabecular bone. Sci. Rep. 10, 13788 (2020).
Abdel-Rahman, E. M. & Hefzy, M. S. Three-dimensional dynamic behaviour of the human knee joint under impact loading. Med. Eng. Phys. 20, 276–290 (1998).
Roshan-Ghias, A., Terrier, A., Bourban, P. E. & Pioletti, D. P. In vivo cyclic loading as a potent stimulatory signal for bone formation inside tissue engineering scaffold. Eur. Cell. Mater. 19, 41–49 (2010).
Robi, K. et al. The physiology of sports injuries and repair processes. In Current Issues in Sports and Exercise Medicine (eds Hamlin, M. et al.) (IntechOpen, 2013). https://doi.org/10.5772/54234.
Acknowledgements
This project has been made possible in part by CZI grants DAF2020-225394 and 2022-316777 (grant DOI https://doi.org/10.37921/331542rbsqvn) from the Chan Zuckerberg Initiative DAF, an advised fund of Silicon Valley Community Foundation and the Royal Academy of Engineering (CiET1819/10). The authors also acknowledge the EPSRC (EP/M019950/1, EP/N025059/1, EP/S025782/1, EP/W034093/1, EP/V011235/1, EP/V011006/1 and IAA EP/X52556X/1).
Funding
This project has been made possible in part by CZI grants DAF2020-225394 and 2022-316777 (grant DOI https://doi.org/10.37921/331542rbsqvn) from the Chan Zuckerberg Initiative DAF, an advised fund of Silicon Valley Community Foundation and the Royal Academy of Engineering (CiET1819/10).
Author information
Authors and Affiliations
Contributions
JL, JC, JJ, and PL contributed to overall experimental design. JL performed the experiments, analysed, and interpreted the data. AH, FT, and ML produced all samples used in the experiments. JL conducted the finite element (FE) analysis with assistance from JC. PL and JJ secured funding and supervised the project. JL drafted the manuscript. AS, JC, AH, JJ, and PL contributed to manuscript review and editing. All authors reviewed and approved the final version of the manuscript.
Corresponding authors
Ethics declarations
Competing interests
The authors declare no competing interests.
Additional information
Publisher’s note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Electronic Supplementary Material
Below is the link to the electronic supplementary material.
Rights and permissions
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 material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
About this article
Cite this article
Liu, J., Chen, J., Heyraud, A. et al. Comparative mechanical characterisation of 13–93 bioactive glass and hybrid scaffolds for bone regeneration. Sci Rep (2026). https://doi.org/10.1038/s41598-026-46620-9
Received:
Accepted:
Published:
DOI: https://doi.org/10.1038/s41598-026-46620-9
