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Biocompatible materials and Multi Jet Fusion

Viability Kit, Molecular Probes Inc, USA) (n = 3 per group). PDL- and CLG-coated surfaces were 27.5° ± 2.00°, 19.93° ±
The dyes were mixed at the ratio of 1:1 and used according 1.14° and 21.33° ± 5.42°, respectively.
to the manufacturer’s instructions. The excitation/emission
wavelength for SYTO9 and PI was 480/500 nm and 3.3. Assessment of cell survival on 3D-printed PA-12
490/635 nm, respectively. Randomly selected areas were surfaces
imaged using a ×20 objective fitted with a fluorescence 3.3.1. Effect of leachate medium
microscope.
L929 fibroblasts and MC3T3e1 osteoblasts cultured in
2.4. Statistical analysis conventional cell culture microwell plate using both
normal and leachate medium adhered to the surface and
Statistical analysis was performed using the Student’s increased in cell density from day 2 to day 4 (Figure 2A,
t-test, and all the values are expressed as mean ± standard Figure S2). Fluorescence staining showed no signs of
deviation. Differences were considered statistically abnormality in the cells. When cultured using the leachate
significant at P < 0.05.
medium, cell morphology was preserved and comparable
3. Results to cells grown in the normal medium. In accordance
with these results, the measurements using quantitative
3.1. Morphological characterization of 3D-printed MTT assay (Figure 2B and C) indicated that cells grown
PA-12 surfaces in the leachate were not affected. Leachate medium did
First, we compared the microstructure and surface not adversely affect the growth of fibroblasts, whereas
morphology of MJF-printed PA-12 (Figure 1A) and casted osteoblasts survived relatively better (P < 0.05) when
PA-12 cell culture chambers (Figure 1B). Representative cultured using the normal medium, but the difference was
SEM images of the surface morphology suggested that the small (17.67% for day 2 and 11.76% for day 4).
3D-printed PA-12 cell culture chambers display a porous, 3.3.2. Cell morphology and viability
rough, and irregular microstructure due to partially
fused PA-12 powders on the surface (Figure 1C), whereas Short-term culture of L929 fibroblasts and MC3T3e1
casted pure PA-12 exhibited a relatively smooth and osteoblasts in the O plasma-treated, uncoated, and
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even texture (Figure 1D). These partially fused powders PDL- and CLG-coated cell culture chambers examined
exhibited a spherical shape with diameters ranging from by fluorescent staining revealed that cells spread well and
~70 to 80 microns (µm). The high-resolution surface exhibited intimate attachment to the surface of 3D-printed
images by laser scanning confocal microscopy, shown in PA-12 cell culture chambers on both day 2 and day 4,
Figure 1E and F, revealed that the average roughness values respectively (Figure 3 and Figures S3–10). Conventional
(R ) of 3D-printed PA-12 had a higher surface roughness polystyrene cell culture plate served as the positive
a
of ~ 9.4 to 10.4 µm in comparison to pure casted PA-12 control. The morphology of cells was maintained in all
(~ 4.3–5.5 µm). the 3D-printed cell culture chambers, and cells formed
confluent layers across the surface topography with an
3.2. Surface functionalization with biomolecules increased cell density observed on day 4. In the background,
Protein adsorption experiments performed on O plasma- stained globular surface structures showed the roughness
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treated and untreated 3D-printed PA-12 cell culture of MJF-printed PA-12. This corroborated with the electron
chambers showed that fluorescent signal increases in a dose- micrographs in Figure 1C, 4A and B. Nevertheless, the
dependent manner (Figure 1G) before plateauing at 1% (w/v) background signal did not affect the visualization of cells.
(Figure 1H). Moreover, the O plasma-treatment showed Rather, the stained background illuminated the topological
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little impact on protein adsorption onto the substrate. context, in which the cells were attached and grew in the
printed PA-12 chamber, providing us with more insight on
The surface energy of 3D-printed PA-12 cell culture
chambers assessed by the water contact angle indicated how the cells would appear on the printed surface. Cells
can still be clearly observed, especially in areas, where
that the uncoated PA-12 cell culture chamber was most
hydrophobic with a contact angle of 88.03° ± 3.63°. Surface there was weaker non-specific noise. Representative results
coating with PDL did not show a significant difference (84° of cells cultured on PDL-coated cell culture chambers are
± 2.62°), whereas the collagen coating significantly reduced shown in Figure 3A. It can be observed that cells, when
the contact angle to 39.4° ± 1.14°, making the surface more grown on the 3D-printed PA-12 surface, exhibited strong

hydrophilic. When additional O plasma-treatment was actin cytoskeleton architectures and prominent nuclei.
2
performed after the surface coating, the contact angles of MTT studies determined the level of cell
all samples decreased. The contact angle values of uncoated, proliferation (Figure 3B and C). The signal increased

Volume 9 Issue 1 (2023) 20 https://doi.org/10.18063/ijb.v9i1.623