3.3 Morphological analysis
The SEM micrographs of a representative 3D printed A-SA-Gel hydrogel
scaffolds are shown in Figure 2E-2M, where surface and cross-sectional
morphologies of the scaffolds and filament structural features were
investigated. It was found that the mesh-like structural features were
obvious and they are structurally intact well. In addition, the SEM
analysis revealed the porous nature of the printed scaffolds with
rectangular architecture (Figure 2E-2F). It is noteworthy that the
intersections of adjacent layers of filaments were tightly intact and
connected (Figure 2G). In addition, the filaments of different layers
were aligned, and the interlayer structure is clearly visible (Figure
2H-2I). The uneven rough surface morphology was observed (Figure 2J).
The surface morphology of single filament was also analyzed and the
results are shown in Figure 2K-2M. The wavy micro rough surfaces were
noticed from the high-resolution images of the scaffold. The average
diameter of the filament was found to be 385μm, which is distinctly
smaller than the 22G nozzle’s inner diameter of 410μm.
To further verify the printability and self-standing ability of the
A-SA-Gel hydrogel suitable to use as a scaffolding system, various
structures were printed out as a model and the results are presented in
Figure 3. A thick cube scaffold structure is shown Figure 3A. A blood
vessel structure can be seen from Figure 3B. The abbreviations of
Shanghai University (SHU) and Vellore Institute of Technology (VIT) were
printed out as pictured in Figure 3C. Importantly, human ear-like
structures were also fabricated without any noticeable deformation and
the results are presented in Figure 3D. All these are the experimental
examples serve as a proof that the multi-material hydrogel developed in
this study can be utilized for 3D printing of various structures and
shapes with high fidelity.