Page 209 - IJB-9-1

International Journal of Bioprinting FeS /PCL scaffold for bone regeneration
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only improved the mechanical properties of the PCL-based FeS particles were incorporated. The FeS particles were
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scaffold, but also enhanced the osteogenic activities of the sterilized in ethanol for 2 hours and under ultraviolet (UV)
rat bone marrow-derived mesenchymal stem cells in vitro for 1 hour. Then, the PCL/FeS melt was printed through a
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and in vivo. In another study, a PCL/gliadin scaffold was 22G nozzle. The applied pressure and nozzle moving speed
reinforced with mesoporous bioglass fibers of magnesium were 400 ± 20 kPa and 1.5 mm/s, respectively. Four scaffold
calcium silicate (mMCS), which improved the compressive types were fabricated: PCL (0 wt% FeS ), PF5 (5 wt% FeS ),
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strength and degradability of the scaffold . The study PF10 (10 wt% FeS ), and PF20 (20 wt% FeS ).
[31]
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found that an increase in mMCS enhanced new bone
formation and ingrowth in a rabbit femur defect model. 2.3. Scaffold characterization
In our previous studies, we fabricated a biocomposite Fourier transform infrared (FT-IR) spectrometer
scaffold assembled from PCL and silica particles using a (Nicolet 6700, Thermo Fisher Scientific, USA) and
3D bioprinting system [32,35] . The silica particles enhanced thermogravimetric analysis (TGA, TGA/SDTA-851,
the mechanical properties, which were dependent on the Mettler-Toledo, Switzerland) were used to analyze the
silica size and weight fraction. In vitro results showed that materials used. The FT-IR spectra were measured in the
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cell proliferation and osteogenic differentiation increased range of 500 to 4000 cm with 8 cm resolution (30 scans).
with decreasing silica particle size and increasing silica The TGA was performed under nitrogen atmosphere from
content. Moreover, new bone formation was found to be room temperature to 750°C with a 20°C/min ramp.
more significant in the rat calvarial defect model when Scanning electron microscopy (SEM; S-4700, Hitachi,
implanted with PCL scaffold incorporated with silica of Japan), energy-dispersive spectroscopy (EDS), and
the smallest size. atomic force microscopy (AFM; Nanowizard AFM, JPK
In this study, we used another biomaterial called Instruments, Germany) were used for the characterization
FeS to improve the mechanical properties based on our of the scaffold morphologies. For AFM, the surface
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previous results. FeS is a naturally occurring biomineral roughness was measured at 50 points randomly selected
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with high insolubility . For thousands of years, FeS on the scaffold surface.
[36]
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has been prescribed as a traditional medicine for bone The compressive modulus of the scaffolds was analyzed
diseases. Various studies have also demonstrated the using a universal testing machine (Instron 3345, Instron,
efficacy of FeS in terms of bone tissue regeneration [37-40] . USA). The prepared samples (1.5 × 2.0 × 2.0 mm ) were
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Therefore, FeS was incorporated in PCL in this study to compressed at a rate of 0.1 mm/s. All values were expressed
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fabricate a scaffold using a 3D melt-printing system for as means ± standard deviation (n = 5).
bone tissue regeneration. Different weight fractions of
FeS were mixed with PCL to evaluate the effect of weight 2.4. In vitro evaluation
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fraction on physical properties such as surface chemistry, A cell recruitment model was designed as described in
[32]
roughness, and mechanical properties. Moreover, FeS our previous study . In brief, the prepared scaffolds
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was found to be non-cytotoxic, as confirmed by in vitro were placed in a donut-shaped alginate-gelatin hydrogel
evaluations performed on the samples using bone marrow with human mesenchymal stem cells (hMSCs) derived
derived mesenchymal stem cells. Finally, a rat calvarial from bone marrow (PromoCell, Germany). Then, the
defect model was used to evaluate the bone formation hMSCs were cultured in Mesenchymal Stem Cell Growth
and neovascularization in the implanted samples. The Medium 2 (PromoCell, Germany) for 7 and 14 days. After
results verified that PCL/FeS scaffolds can be a potential the scheduled culture period, the samples were stained
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candidate for hard tissue regeneration. with 4′,6-diamidino-2-phenylindole and observed using a
confocal microscope.
2. Materials and methods 2.5. Animal model
2.1. Materials This animal study was approved by the local animal ethics
PCL (M = 45,000 g/mol) was purchased from KD R&D committee (approval number: DGMIF-20100801-00) and
n
Center (South Korea), and FeS (particle size: 100.8 ± performed in accordance with ISO 10993-6: Biological
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13.1 mm) was purchased from a local oriental medical evaluation of medical devices—Part 6: Tests for local effects
clinic (South Korea). after implantation. Forty-eight Sprague-Dawley rats (300 g,
male, OrientBio, South Korea) were randomly divided
2.2. Scaffold fabrication into four groups (n = 12). The rats were anesthetized by
The scaffolds used in this study were prepared using a 3D injecting Zoletil (50 mg/mL) and Rompun (23.32 mg/mL)
printing system (Baobab Root-1, Baobab Healthcare Inc., intraperitoneally. The scaffolds were then implanted into
South Korea). First, PCL pellets were melted at 110°C before the holes (8 mm) that were created in the cranial bone

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Volume 9 Issue 1 (2023)olume 9 Issue 1 (2023) 201 https://doi.org/10.18063/ijb.v9i1.636