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International Journal of Bioprinting 3D printing technology in neurotrauma

extends to a variety of materials, including biocompatible structures at a relatively fast production rate. 73,74 On the
polymers, living cells, and therapeutic compounds. 61,62 negative side, it has a lower resolution, making it less
In nervous system injuries, inkjet 3D printing plays suitable for applications requiring fine details. Besides, cell
an important role, offering notable advantages such as viability may be influenced by pressure in pressure-based
precision and customization. Inkjet 3D printing provides a systems, necessitating careful control. The layer-by-layer
high degree of precision in the deposition of cells, growth stacking characteristic of extrusion-based 3D printing can
factors, and biomaterials within 3D constructs. This result in visible layer lines that may affect surface quality and
precision allows for the accurate replication of the intricate biocompatibility. Therefore, while it excels in customization
nervous system microenvironment and the customization and cost-effectiveness, extrusion 3D printing may not be
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of treatments to suit individual patients’ needs. ideal for high-precision applications and may require special
Empirical evidence also underscores the effectiveness of attention to pressure-sensitive cell viability.
inkjet 3D-printed constructs in promoting neural tissue
regeneration. A hallmark feature of inkjet 3D printing 2.2.3. Stereolithography
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is the precision in delivering therapeutic agents, thereby Stereolithography (SLA) has emerged as a remarkably
minimizing side effects and optimizing therapeutic precise and adaptable technology across various domains.
outcomes. 61,63 Biocompatible scaffolds created through It functions based on the principle of photopolymerization,
inkjet 3D printing faithfully replicate the native CNS employing a laser crosslinking mode. The process involves
environment, providing essential support for cell growth, the incremental layer-by-layer construction of 3D objects
differentiation, and the formation of neural connections, by selectively solidifying liquid resin or photopolymer
all crucial aspects of CNS repair. 63,65,66 Compared to other materials with a laser beam, following a 2D image of
3D printing technologies, inkjet 3D printing excels in the intended cross-section, until the entire 3D structure
terms of precision and resolution, and thus is crucial for is formed. SLA technology offers distinct advantages
constructing intricate neural structures. 60,63 However, compared to other 3D printing methods. Its remarkable
features include:
inkjet 3D printing may have limited material compatibility.
Additionally, it is worth noting that inkjet 3D printing (i) High precision. SLA stands out for its ability to
may have limitations in terms of speed, which can be a achieve high-resolution printing, boasting a
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drawback for high-volume printing. 67 remarkable resolution of approximately 100 μm. It
makes it a preferred choice for crafting intricate and
2.2.2. Extrusion 3D printing finely detailed structures.
Extrusion 3D printing, a versatile additive manufacturing
technique, distinguishes itself from inkjet printing by (ii) Complex geometrical capabilities. SLA excels in
fabricating 3D structures line-by-line through a movable producing objects with intricate and highly complex
nozzle driven by pneumatic or mechanical dispensing geometrical features. This capability allows for
systems. This method provides a resolution typically ranging customization and precise design, offering versatility
from 100 to 500 μm, making it ideal for a wide range of in meeting diverse requirements.
applications. 68,69 In the field of regenerative medicine, (iii) No restrictions on cell viscosity. Unlike other
custom 3D printing systems based on micro-extrusion have techniques, SLA imposes no constraints on the
been developed, enabling the creation of constructs that viscosity of cells, rendering it adaptable to various
significantly enhance functional recovery after neurotrauma. bioink formulations.
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For instance, 3D-printed collagen/chitosan scaffolds based
on micro-extrusion have shown promise in repairing nerve (iv) Reduced toxicity with visible light. In response
defects after TBIs. In the realm of bioprinting, it has been to concerns about cell safety, visible light
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applied to develop scaffolds laden with various cell types, photopolymerization has been explored in SLA.
such as NSCs and ectomesenchymal stem cells (EMSCs), Compared with traditional ultraviolet light, this
fostering the recovery of injured CNS. 71,72 Compared to approach proves to be less harmful to cells.
other 3D printing methods, it offers several advantages In the sphere of regenerative medicine, SLA
and disadvantages. On the positive side, it is cost-effective technology holds substantial promise for neurotrauma
and suitable for projects with limited budgets, allowing for treatment. It facilitates the meticulous creation of scaffolds
the creation of highly customized bioscaffolds and tissue characterized by controlled structures, including multi-
engineering solutions tailored to individual patient needs. channels, oriented fibers, and the incorporation of cells
It also provides versatility in material choices, including and neurotrophic factors. These elements play a pivotal
bioceramics and biopolymers. Additionally, extrusion- role in promoting the regeneration of nerves. But SLA
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based 3D printing can manufacture high-density cell technology also has some shortcomings, such as limited

Volume 10 Issue 3 (2024) 66 doi: 10.36922/ijb.2311