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3D-printed borate glass scaffolds for bone repair
degradation in vitro are dependent on porosity and 4. Rahaman MN, Day DE, Bal BS, et al., 2011, Bioactive Glass
architecture. Among the five different architectures in Tissue Engineering. Acta Biomater, 7:2355–73.
considered in this study (cubic, spherical, x, 5. Fu Q, Rahaman MN, Fu H, et al., 2010, Silicate, Borosilicate,
gyroid, and diamond), cubic scaffolds provided the and Borate Bioactive Glass Scaffolds with Controllable
highest compressive strength (16 MPa) at lower Degradation Rate for Bone Tissue Engineering Applications.
porosities (<35%) and spherical scaffolds had I. Preparation and In Vitro Degradation. J Biomed Mater Res
the highest strength (4 MPa) at higher porosities Part A, 95A:164–71. DOI: 10.1002/jbm.a.32824.
(>60%). Gyroid and diamond scaffolds recorded 6. Jung S, Day D, 2009, Conversion Kinetics of Silicate,
greater strength reduction after 1-week immersion Borosilicate, and Borate Bioactive Glasses to Hydroxyapatite.
in SBF, likely because of their biomimetic Phys Chem Glas, 50:85–8.
architectures mimicking natural bone. This study 7. Balasubramanian P, Kolzow J, Chen RR, et al., 2018,
has shown that powder bed fusion processes can Boron-containing Bioactive Glasses in Bone and Soft Tissue
be used to fabricate scaffolds with controlled rates Engineering. J Eur Ceram Soc, 38:855–69.
of strength degradation and bone regeneration by 8. Yuan S, Shen F, Chua CK, et al., 2019, Polymeric Composites
selecting appropriate architecture and bioactive for Powder-based Additive Manufacturing: Materials and
glass composition. These scaffolds can be used to Applications. Prog Polym Sci, 91:141–68.
repair specific regions of trabecular bone, based 9. Ng WL, Lee JM, Zhou M, et al., 2020, Vat Polymerization-
on functional requirements. Cubic and diamond based Bioprinting Process, Materials, Applications and
scaffolds with ~50% porosity and ~1 mm pore Regulatory Challenges IOP Science. Biofabrication,
size were used to treat a full-thickness 4.6 mm 12:022001. DOI: 10.1088/1758-5090/ab6034.
diameter rat calvarial defect with or without 10. Goh GD, Yap YL, Tan HK, et al., 2020, Process Structure
BMP-2. There was no significant difference in Properties in Polymer Additive Manufacturing via Material
mineralized bone formation for defects treated Extrusion: A Review. Crit Rev Solid State Mater Sci, 45:113–
with cubic and diamond architectures after 6 weeks 33. DOI: 10.1080/10408436.2018.1549977.
of implantation. However, a higher percentage 11. Cai S, Xi J, 2008, A Control Approach for Pore Size
of fibrous connective tissue and high osteoblast Distribution in the Bone Scaffold Based on the Hexahedral
activity was observed in the defects treated Mesh Refinement. CAD Comput Aided Des, 40:1040–50.
with diamond scaffolds. The addition of BMP-2 DOI: 10.1016/j.cad.2008.09.004.
significantly increased the bone regeneration from 12. Melchels FP, Bertoldi K, Gabbrielli R, et al., 2010,
6% (without BMP-2) to 40% of the defect area. Mathematically Defined Tissue Engineering Scaffold
Architectures Prepared by Stereolithography. Biomaterials,
Acknowledgments 31:6909–16. DOI: 10.1016/j.biomaterials.2010.05.068.

13. Challis VJ, Roberts AP, Grotowski JF, et al., 2010,
The glasses used in this work were provided by
Mo-Sci Corporation, Rolla, MO. Authors thank Prototypes for Bone Implant Scaffolds Designed via
Natalie Holl for help on technical editing and Topology Optimization and Manufactured by Solid Freeform
acknowledge the assistance of Jacob Mendez and Fabrication. Adv Eng Mater, 12:1106–10. DOI: 10.1002/
Bradley Bromet for image analysis. adem.201000154.
14. Feng J, Fu J, Li Z, et al., 2018, A Review of the Design
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