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Bioprinting of multimaterials with computer-aided design/computer-aided manufacturing
Table 2. Consideration factors and comparison between the different file processing methods.

Intentional spacing BioSeg file processing Conventional file processing
Consideration factors Bioprinter’s compatibility issues Material’s compatibility issues
Axis of movement Curing mechanism of build material
Height of platform Stability of material prior to curing
Distance between printed model and print head Interaction between different
Material’s compatibility issues materials
Curing mechanism of build material
Stability of material prior to curing
Interaction between different materials
Advantages Shorten printing duration Straightforward process
Greater design of freedom in depositing build
material

4.2 Left ventricle A

A model of the heart’s left ventricle is fabricated to
show the capability of proposed new method for
realistic bioprinting applications. Based on the file
segmentation criteria, the current model does not
require fragmenting the CAD model into smaller
part files. The 3D CAD images of the structure
fabricated, together with the generated support B
structure, are shown in Figure 5. C
The printed construct was cured under exposure
of UV lamp before support material removal by
washing with cold water. The curvature of the left
ventricle printed was present even without the
support structure, as shown in Figure 5C. Figure 5. Three-dimensional image of the left
ventricle (A) computer-aided design model
5 Conclusion with build (red) and support (green) materials
corresponding with the respective red and green
Multimaterial deposition is of increasing interest area of printed construct, (B) side profile of
in bioprinting for improving print fidelity in 3D printed construct, (C) curvature of printed left
bioprinting. Specifically, the use of build and ventricle preserved after support material removal
support materials has been demonstrated in several (top view, curvature mapped with red dotted line).
researches to build engineered tissue constructs
with structural stability. The study on support
material generation and print path optimization is the printed construct through the formation of
of great relevance for bioprinting as demonstrated chemical bonds between polymer chains (gelatin
across other additive manufacturing technologies.
Material selection is imperative in a build/ methacrylate).
support printing setup for building biological In this paper, we have also demonstrated a
constructs with shape fidelity. Build materials have proof of concept to highlight the novelty in file
been chosen to facilitate cross-linking at different segmentation for multimaterial deposition in
degrees. The first degree of cross-linking uses bioprinting. This method can be used to fully
hydrogel with rapid gelation mechanism (sodium utilize the tool changing capabilities of bioprinter
alginate and calcium chloride) to provide partial to print multimaterials at a reduced print time.
mechanical stability before fully cross-linking Considerations in terms of machine and materials

70 International Journal of Bioprinting (2020)–Volume 6, Issue 1