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RESEARCH ARTICLE

Nano-Hydroxyapatite Bone Scaffolds with Different

Porous Structures Processed by Digital Light Processing

3D Printing

Haowen Liang 1,2† , Yue Wang 1,3† , Shangsi Chen , Yang Liu , Zhengbai Liu , Jiaming Bai *
2
1
3
4
1 Shenzhen Key Laboratory for Additive Manufacturing of High-performance Materials, Department of Mechanical and
Energy Engineering, Southern University of Science and Technology, Shenzhen, China
2 School of Innovation and Entrepreneurship, Southern University of Science and Technology, Shenzhen, China
3 Department of Mechanical Engineering, The University of Hong Kong, Hong Kong SAR, China
4 Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, China
† These authors contributed equally to this work

Abstract: The morphologies and structures of the scaffold have a significant influence on their mechanical and biological
properties. In this work, different types of porous structures: Triply periodic minimal surface-Schwarz primitive (P), body-
centered cubic, and cubic pore-shaped (CPS) hydroxyapatite scaffolds with ~70% porosity were fabricated through digital
light processing (DLP) 3D printing technology. The compressive properties and in vitro cell evaluations such as cell
proliferation and attachment morphology of these scaffolds were systematically compared. The results showed that the CPS
scaffolds exhibited the highest compressive strength (~22.5 MPa) and modulus (~400 MPa). In addition, the CPS scaffolds
also performed the most active cell metabolisms as compared to other two structures, which may account for the larger pore
size and smaller curvature of the substrate. This study provides a general guidance for the fabrication and selection of porous
bone scaffolds processed by DLP 3D printing.
Keywords: Nano-hydroxyapatite; Digital light processing; Bone scaffolds; 3D printing

*Correspondence to: Jiaming Bai, Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Shenzhen,
Guangdong Province, China; baijm@sustech.edu.cn
Received: October 26, 2021; Accepted: December 20, 2021; Published Online: January 17, 2022

Citation: Liang H, Wang Y, Chen S, et al., 2022, Nano-hydroxyapatite Bone Scaffolds with Different Porous Structures Processed by Digital
Light Processing 3D Printing. Int J Bioprint, 8(1):502. http:// doi.org/10.18063/ijb.v8i1.502

1. Introduction for treating bone lesions. Scaffolds play an important role in
BTE for providing a three-dimensional (3D) environment
Bone defects caused by trauma injuries, diseases, and for cell attachment, adhesion, growth, and proliferation
complications that occurred in the bone regenerating
process have been a critical medical problem in the until the injured bone has regenerated its own properties
current society [1-4] . However, bone defects cannot heal and functions. There are several requirements for tissue
themselves without surgical interventions when the engineered scaffolds. The paramount requirements for
defects are larger than the critical size [5-7] . Traditional BTE scaffolds are biocompatibility and non-toxicity [10-12] .
surgical operations, including autografts and allografts, Hydroxyapatite (HA) is chemically similar to the
have inevitable drawbacks, such as supply shortage, inorganic phase of native bone, possessing incomparable
the need for second surgery, and occurrence of immune biological advantages such as osteoconductivity,
responses, which increase the implantation risk and osteoinductivity, and biocompatibility. Therefore, it
hinder their further applications in clinic [8-10] . is widely regarded as a promising material for bone
With rapid development in recent years, bone tissue scaffolds. Second, bone scaffolds should have sufficient
engineering (BTE) is considered a new substitutive therapy mechanical strength and stiffness to provide physical
© 2022 Author(s). This is an Open Access article distributed under the terms of the Creative Commons Attribution License, permitting distribution and
reproduction in any medium, provided the original work is properly cited.
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