Page 64 - IJB-9-3

International Journal of Bioprinting Peritoneal scaffolds for the peritoneal adhesion prevention

Table 1. Adhesion score We observed the morphology of MEW-printed PCL
scaffolds. The PCL scaffolds were fabricated with a high
Grade Grade description resolution and satisfactory fidelity (Figure 1A–C). The
1 Filmy and easy to separate or separates spontaneously by fibers were 15–30 μm and arranged at the as-expected
accessing the peritoneal cavity. angles (30°, 60°, or 90°).
2 Blunt dissection possible, beginning vascularization but no
visible bleeding when separated. The PCL scaffolds presented different tensile stress–
3 Lysis possible by sharp dissection only, clear vascularization, strain curves when the fibers were crossed differently
visible bleeding when separated. (Figure 1D). The smaller crossing angles led to a significant
4 Lysis possible by sharp dissection only, organs strongly reduction in tensile strength, Young’s modulus, and fracture
attached with severe adhesions, damage of organs when energy, and an increase in elongation length ratio at break
separated. (Figure 1E–H). This implied that the reduction of crossing
angles lessened the stiffness, but increased the flexibility of
the button (20 times) and the adjacent liver, cecum, small the PCL scaffolds, which ensured that the scaffold adapted
intestine, and large intestine (7 times) could be performed to the shear forces of organ movements.
with a surgical brush (depending on the desired severity of The PCL scaffolds showed a hydrophobic property that
adhesions). The peritoneum and skin were closed with 4-0 interrupted the exchange of inflammatory exudate in the
silk sutures . lesion site; therefore, they worked as a physical barrier
[25]
[30]
2.12. Adhesion scoring for the prevention of tissue adhesion . Reduction of the
All mice were given 200 mg/kg of ketamine hydrochloride crossing angles of the fibers improved the hydrophobic
and 10 mg/kg of xylazine hydrochloride to make them property by presenting larger contact angles (Figure 1I).
unconscious on postoperative days 1 and 7, after which
the abdominal cavity was cut open in the middle of each 3.2. Fabrication and optimization of peritoneal
animal. Adhesions were scored based on their tensile scaffolds
strength and vascularization as previously described To mimic the composition and function of the peritoneum,
(Table 1) . we extracted murine primary peritoneal mesothelial cells
[26]
as a constituent of the peritoneal scaffold (Figure S1).
2.13. Histological study More than 90% cells were coexpressed with vimentin
To carry out the histological study of the adhesion sites, (red fluorescence) and PCK (green fluorescence), which
representative samples were selected. The button and indicated that the purity of primary peritoneal mesothelial
adherent tissues were excised, fixed in 4% buffered cells was >90%. The mesothelial cells (Figure 2Ai) were
formaldehyde solution, embedded in paraffin sections, and seeded on the PCL scaffolds with different fiber angles
[27]
stained with HE and Masson stain . (30°, 60°, and 90°) to screen the most suitable fiber
arrangement for mesothelial cell growth (Figure 2Aii–iv).
2.14. Statistical analysis Light microscopy and immunofluorescence showed that
Data are expressed as mean ± SEM. Data were analyzed mesothelial cells adhered to the PCL scaffolds (Figure 2B
using GraphPad Prism 9 software by Student’s t test and C). Compared with the 60° and the 90° scaffolds, the
(unpaired and two-tailed). The values were considered 30° scaffold had a higher rate of mesothelial cell attachment
significantly different at P < 0.05.
(Figure 2D) and was more conducive to cell proliferation
3. Results and discussion (Figure 2E).
Laronda et al. have found that cell localization and
[29]
3.1. Fabrication of PCL scaffolds based on MEW survival in 3D-printed microporous hydrogel scaffolds
To obtain PCL scaffolds with fibers in a diversity of depend on the geometry of the scaffold pores. The 30° and
crossing angles, a custom-built MEW printer was used 60° scaffolds provided multiple edges to support cells, while
to deposit PCL onto a substrate with the assistance of a the pores of 90° scaffolds limited cell–scaffold interactions.
high-voltage electric field (Scheme 1). The printing path Cell survival was positively correlated with the number of
was predesigned in which the fibers were crossed at 30°, strut contacts, which was improved as the amount of cell–
60°, or 90°, because the angles may affect adhesion of cells scaffold interaction increased. Such a phenomenon also
loaded in the scaffolds [28,29] . The primary mesothelial cells existed in the MEW-printed PCL scaffolds.
were seeded on the PCL scaffolds to produce the peritoneal
scaffolds, which aimed to form a barrier to separate the The scaffold fiber arrangement could guide the
injured visceral organs from the abdominal wall physically direction of cell proliferation. Mesothelial cells grew along
and biologically. the longitudinal axis on the 30° scaffolds (Figure 2Cii), but

Volume 9 Issue 3 (2023) 56 https://doi.org/10.18063/ijb.682