Challenges on optimization of 3D-printed bone scaffolds

Abstract

Advances in biomaterials and the need for patient-specific bone scaffolds require modern manufacturing approaches in addition to a design strategy. Hybrid materials such as those with functionally graded properties are highly needed in tissue replacement and repair. However, their constituents, proportions, sizes, configurations and their connection to each other are a challenge to manufacturing. On the other hand, various bone defect sizes and sites require a cost-effective readily adaptive manufacturing technique to provide components (scaffolds) matching with the anatomical shape of the bone defect. Additive manufacturing or three-dimensional (3D) printing is capable of fabricating functional physical components with or without porosity by depositing the materials layer-by-layer using 3D computer models. Therefore, it facilitates the production of advanced bone scaffolds with the feasibility of making changes to the model. This review paper first discusses the development of a computer-aided-design (CAD) approach for the manufacture of bone scaffolds, from the anatomical data acquisition to the final model. It also provides information on the optimization of scaffold's internal architecture, advanced materials, and process parameters to achieve the best biomimetic performance. Furthermore, the review paper describes the advantages and limitations of 3D printing technologies applied to the production of bone tissue scaffolds.

Keywords: Additive manufacturing; Bioprinting; Composites; Computational design; Customized bone scaffold; Functionally graded materials; Metadata analysis.

Fig. 1

a 3D reconstruction of CT data (reprinted with permission from Springer Nature, J. H. Ryu et al. [23] copyright (2004)), and b reverse engineering approach to provide CAD model (reprinted from Sun et al. [19] Copyright (2005), with permission from Elsevier)

Fig. 2

a The scaffold designed by periodic repeating of unit cells created in ABAQUS software, and b Boolean operation between the scaffold block model and the actual model of the mandible bone defect (reprinted from N. Vitković et al. [68] copyright (2018), with permission from Elsevier)

Fig. 3

Optimization process of scaffold internal architecture

Fig. 4

Optimization process of scaffold material

Fig. 5

a Percentages of different 3D printing approaches investigated for bone scaffolds; b percentages of 3D bioprinting uses in different tissue engineering applications, and c comparison of uses of different 3D bioprinting approaches over time (based on Scopus search, type of document was article, keywords for a 3D printing and bone scaffold and the technique name, b 3D bioprinting with each application name, and c 3D bioprinting and name of approach)

Fig. 6

Schematic of laser-based 3D printing technologies: a SLA, b SLS/SLM, c EBM, d LENS, e 2PP, and f laser-based bioprinting

Fig. 7

Schematic of a FDM, b MJ, c AJP, and b IJP

Fig. 8

Process parameters and material variables for 3D printing technologies