Page 61 - IJB-9-3

International Journal of Bioprinting Peritoneal scaffolds for the peritoneal adhesion prevention

The most popular method to prevent postoperative electrowriting (MEW) technology can overcome the
peritoneal adhesion is the implantation of biomaterial above-mentioned drawbacks . MEW enables highly
[20]
products, including artificial films, fluids, or gels . These controllable deposition of ultrafine fibers, which can
[6]
methods, however, do not completely resolve the problem provide a mechanical support for cell implantation and
of peritoneal adhesion [7,8] . There are two important facilitate the guidance of cell orientation due to its ordered
approaches to prevent peritoneal adhesions: (i) blocking structure .
[21]
the contact of injured visceral organs with neighboring We designed a peritoneal scaffold by seeding primary
tissues, and (ii) repairing damaged peritoneum. Peritoneal peritoneal mesothelial cells onto an MEW-printed
injury forms unintended tissue connections, upon which polycaprolactone (PCL) scaffold, thereby mimicking the
progressive fibrosis and vascularization enhance the native peritoneum (Scheme 1). The scaffold prevented the
connections. Therefore, the design of biomaterials that can formation of peritoneal adhesions with synergistic effects
interrupt the connections is a research hotspot. by providing a physical and biological barrier against
In recent years, cell therapy has become the frontier macrophage infiltration, and participated in peritoneal
of preventing peritoneal adhesion, but there are still repair.
some limitations . For example, Tomoya et al. prevented
[9]
peritoneal adhesions by inducing in situ barrier formation of 2. Materials and methods
abdominal macrophages through injection of interleukin-
4c . The effect of drug-induced cell barriers is uncertain 2.1. Fabrication of PCL scaffolds with MEW
[10]
because of the heterogeneous immune response capacity The scaffolds with the fibers in different crossing angles
of the body. Inagaki et al. fabricated cell sheets from fetal (30°, 60°, and 90°) were fabricated based on a custom-built
liver mesothelial cells, which prevented postoperative MEW printing device (EFL-MDW5800; Suzhou Intelligent
adhesions and promoted liver regeneration . However, Manufacturing Research Institute, China). The device
[11]
simple mesothelial cell sheets are mechanically weak consists of motorized XYZ stages with a collector, syringe
and hard to fix surgically, making it difficult to meet real with a nozzle, two heaters for heating the PCL polymer
clinical scenario requirements. (CAPA6800; Perstorp Co., Ltd, Sweden), high-voltage
generator, and pneumatic system to adjust the extrusion
In this study, we designed a novel peritoneal scaffold pressure. During printing, the syringe and nozzle was
based on the constitution and function of native heated to 85°C, and melted PCL was extruded through a
peritoneum. The human peritoneum is a complex tissue syringe with a 150-μm nozzle. The pumped air pressure
mainly composed of mesothelial cells , which forms a was 120 kPa, the distance between collector and nozzle
[12]
natural physiological barrier against organ adhesion and was 2.5 mm, the voltage was set at 4500 V, and the printing
abrasion . Peritoneum is capable of regeneration via a speed was 80 cm/min.
[13]
unique healing mechanism through which mesothelial
cells migrate from the lesion edge to the center, and detach 2.2. Observation of the microstructure
and settle on the lesion site from opposite or distant areas. The structure images of PCL scaffolds with the fibers
These free-floating mesothelial cells, detected in the plasma crossed in varied angles (30°, 60°, and 90°) were recorded
fluid, proliferate and disperse to repopulate the injured with a scanning electron microscope (TM3000; Hitachi,
area [14,15] . This method of peritoneal repair enables us to Japan). The scaffolds with varied crossing angles were
construct a mesothelial cell barrier that blocks peritoneal imaged after being coated with a thin layer of gold.
adhesion to organs and participates in repairing the 2.3. Measurements of mechanical strength
damaged peritoneum . The stretching capabilities of PCL scaffolds with the fibers
[16]
To provide a carrier for the growth of mesothelial cells, in different crossing angles (30°, 60°, and 90°) were tested
we applied three-dimensional (3D) printing technology by a universal material testing machine (CMT2103; MTS,
to fabricate a scaffold suitable for cell growth . This Eden Prairie, MN, USA) according to the regular method
[17]
[22]
will provide a stable growth environment for mesothelial used in our laboratory . The PCL scaffolds were tailored
cell attachment with appropriate mechanical strength. with a length of 20 mm, width of 10 mm, and thickness of
3D printing technology has the natural advantage of 10-layer PCL sheets. After the PCL scaffolds were clamped
customization [18,19] . The low technical precision (100– by two parallel metal clips, the upper clip stretched the
200 µm) of conventional 3D printing, such as fused PCL scaffolds at a rate of 10 mm/min until the scaffolds
deposition modeling, and the uncontrollable morphology were torn up. In this way, the tensile stress (τ)–strain (ε)
of electrostatic spun jet fibers fail to provide a suitable curve could be drawn. The fracture energy (U) of the PCL
scaffold for mesothelial cells. The newly developed melt scaffolds was calculated using Equation I by figuring out

Volume 9 Issue 3 (2023) 53 https://doi.org/10.18063/ijb.682