Page 273 - IJB-10-2

International Journal of Bioprinting Microfluidic spinning for neural models

used in fields such as tissue engineering and biomedical microfluidic spinning to prepare microfibers; however,
research. Microfibers are similar, in terms of form and the surface of CaA microfibers lacks the cell adhesion sites
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structure, in most tissues and organs of living organisms, of cultured cells, hindering the diffusion and migration
such as the myocardium, nerve bundles, and other of encapsulated cells. 27,28 Recently, GelMA has received
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5,6
luminal structures (e.g., blood vessels, pulmonary increasing attention in the field of tissue engineering. 29,30
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bronchi, and intestinal cavities ). Thus, microfibers can GelMA is a synthetic polymer material obtained from the
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be used to reconstruct biomimetic tissues and organs in reaction between gelatin and methacrylic anhydride. The
vitro. Furthermore, through microfiber assembly, more principle behind GelMA-forming hydrogel is that, under
functional 3D biomimetic bodies can be formed, thereby ultraviolet (UV) irradiation, the unstable C=C bonds in
providing new models for disease model construction, the GelMA molecule break, producing active free radicals,
drug evaluation, and personalized diagnosis. and after the induction of the photoinitiator, a hydrogel
with a network structure is formed. As a substitute for
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Commonly used preparation methods for microfibers
include melting, electrospinning, and wet spinning. 10-14 gelatin, GelMA is commendable for its biocompatibility,
which is far superior to that of other synthetic materials,
Owing to the presence of high-temperature and high- and its ability to simulate the extracellular matrix. 32-34 In
pressure environments, volatile organic solvents, GelMA hydrogels loaded with cells, researchers observed
and high shear stress during the melt-spinning and
electrospinning processes, which can affect cell viability, high cell viability (>80%) and the formation of vascular
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prepared microfibers cannot be directly used for cell networks. The excellent biocompatibility of the GelMA
encapsulation and are often prepared as thin membrane hydrogel and its ability to rapidly solidify in situ promote
materials for cell adhesion and growth. However, wet its application in the construction of cells/tissues in vitro,
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36,37
spinning, especially microfluidic spinning technology especially in vascular tissue engineering. In addition
developed from microfluidic technology, has become to GelMA, RGD-modified alginate is also suitable for
vascular endothelial cell culture, yielding effects similar
the primary method for preparing cell-loaded microfiber to that of GelMA, but comparatively, GelMA material is
scaffolds because of its mild reaction conditions, accurate more readily available. 38
and controllable operation, and the use of biogel materials
with good biological properties. In addition, microfluidic In recent years, the accelerated population aging has
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spinning forms a coaxial laminar flow by injecting sample significantly raised the prevalence of Parkinson’s and
and sheath flow solutions with a certain viscosity into Alzheimer’s diseases. 39,40 Since there are no drugs available
microchannels, which further undergo chemical or to reverse the axonal damage causing these degenerative
physical crosslinking in the preparation of microfibers. diseases of the nervous system, rebuilding nerve axons
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Functional microfibers with various special morphologies in vitro emerges as a feasible strategy. Toward this end, a
and components can be obtained by adjusting the number pathological/physiological model built with an assembly
of flow channels and injection strategies, particularly of microfibers and microchips is required to observe cell
hollow microfibers with tubular structures, which is growth, perform functional testing in a 3D environment
beneficial for 3D cell culture and tissue biomimetics. 18-23 in vitro, offer a platform to study the mechanism of disease
For examples, based on a microfluidic platform with occurrence, and conduct drug evaluations.
an attached photopolymerization device, Aykar et al. In this study, we prepared a microfluidic spinning
prepared poly(ethylene glycol diacrylate) (PEGDA)- microchip template and microfiber assembly microchip
based hollow fibers as self-standing microvessels with template with different channel heights using 3D printing
biocompatibility/cytocompatibility. Also, Lee et al. technology in one step and then prepared a microfluidic
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reported 3D artificial microvessels based on HIVE-78 spinning microchip and microfiber assembly microchip
cell-encapsulated hollow alginate microfibers and co- using the polydimethylsiloxane (PDMS) molding
cultured with smooth muscle cells (HIVS-125). Zhao et method. Hollow calcium alginate (CaA)/GelMA
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al. prepared grooved microfibers by co-spinning sodium composite microfibers with different numbers of cavities
alginate (NaA) with GelMA, and the muscle cells grown were prepared using a microfluidic spinning microchip
on the microfibers showed good viability and ordered and various flow strategies. The composition and
alignment. The proposed method has the potential to structure of the microfibers were characterized using
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replicate various arranged microstructures in vivo, such infrared spectroscopy and scanning confocal microscopy.
as nerve bundles and blood vessels. Then, human umbilical vein endothelial cells (HUVECs)
Cell-loaded microfibers have been prepared using were seeded and cultured in CaA/GelMA composite
synthetic or natural polymer materials. Ionic crosslinking hollow microfiber tube walls, and biomarkers related to
of NaA and calcium chloride (CaCl ) is often adopted in vascular endothelialization were characterized. Finally,
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Volume 10 Issue 2 (2024) 265 doi: 10.36922/ijb.1797