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International Journal of Bioprinting 3D printing technology in neurotrauma

Table 1. Different types of 3D printing and bioprinting technologies for neurotrauma treatment
Technology Suitable materials Advantages Disadvantages
FDM Thermoplastic filaments, High speed; low cost; Poor mechanical features; poor surface
e.g., polyurethane, ABS, PCL, and PLA environmental protection properties; limited availability of suitable
thermoplastic polymer
NFES Thermoplastic and functional Micron/Nanoscale resolution; low cost; Possible cytotoxicity of solvents and the
polymer materials, compatible with various materials electric field
e.g., PCL and PLA
TPP Photopolymer, Highest resolution; directly perform Cumbersome printing process; high cost
e.g., polypyrrole, GelMA, and PEGDA photopolymerization at any point
Inkjet Thermoplastic and functional polymer High resolution; low cost; high Low mechanical strength; low droplet accuracy;
materials, fabrication speed relatively low cell viability
e.g., collagen, PCL, and PLA
Extrusion Thermoplastic and functional Low cost; multiple materials mixed Lower resolution than inkjet; low fabrication
polymer materials, printing; higher cell viability speed; nozzle clogging
e.g., alginate dialdehyde, GelMA,
PLLA, and PLGA
SLA Photopolymer, Higher resolution; high fabrication High cost; limited availability of suitable
e.g., GelMA, HAMA, and PEGDA speed; personalization hydrogels; possible cytotoxicity of photoinitiator
and uncured resin
DLP Photopolymer, Higher resolution; no limitation on cell High cost; limited availability of
e.g., GelMA, HAMA, and PEGDA viscosity; no artificial interfaces suitable hydrogels
Abbreviations: ABS, acrylonitrile butadiene styrene; DLP, digital light processing; FDM, fused deposition modeling; GelMA, gelatin methacrylate;
HAMA, hyaluronic acid methacrylate; NFES, near-field electrospinning; PEGDA, poly (ethylene glycol) diacrylate; PLA, poly lactic acid; PLGA,
poly lactic-co-glycolic acid; PLLA, poly-L-lactic acid; PCL, polycaprolactone; TPP, two-photon polymerization; SLA, stereolithography.

poly-e-caprolactone (PCL) scaffolds, which can serve as This resolution makes it particularly suitable for fabricating
guidance cues for regenerating nerve fibers and facilitating delicate structures for applications in neurotrauma. Accardo
functional recovery. These scaffolds allow therapeutic et al. produced an intricate 3D scaffold from polyethylene
agents and biomaterials to be incorporated directly into glycol diacrylate (PEGDA) using the TPP method. These
the printed constructs. In addition, Song et al. used 3D scaffolds proved conducive to the survival of Neuro
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NFES based on polymer solutions to fabricate scaffolds, 2A cells and nerve regeneration. Similarly, Marino et
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and loaded ECM hydrogel with drugs on the scaffolds to al. applied the TPP method to create high-resolution
promote the differentiation of neural stem cells (NSCs). scaffolds, revealing that neurons exhibited better shape
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However, this technique cannot directly print cells because when cultured on the scaffold. Besides, the TPP method
the electric field can be deleterious, and most solvents can also print other forms of delicate constructs such as
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exhibit cytotoxicity. microneedle arrays to carry drugs to treat neurotrauma.
In summary, TPP is an advanced technology offering the
2.1.3. Two-photon polymerization highest resolution and the capability to fabricate intricate
The two-photon polymerization (TPP) technology involves structures that show potential in neurotrauma. However,
the photopolymerization process initiated by two-photon TPP also has the disadvantages of a cumbersome printing
absorption at the high-intensity laser focal point generated process, high cost, and inability to print cells directly.
by a near-infrared femtosecond pulsed laser beam, which
was initially introduced by Japanese scholars in recent 2.2. 3D bioprinting technology
years. 52,53 Notably, two-photon absorption only occurs 2.2.1. Inkjet 3D printing
at the focal point, distinguishing it from the traditional Inkjet 3D printing, an evolved version of traditional
stereolithography method. This unique characteristic two-dimensional (2D) inkjet printing, operates on the
enables TPP to complete photopolymerization anywhere foundational principle of controlled material deposition
in the 3D space, transcending surface limitations. 54,55 One within a 3D space. This technology employs print heads
of the most remarkable aspects of TPP is its potential for equipped with nozzles to dispense minute droplets of
solidification resolutions below the diffraction limit of the material onto a substrate. By systematically layering
applied light, allowing for 3D printing at a nanoscale and these droplets, intricate 3D structures are meticulously
achieving a lateral spatial resolution of less than 100 nm. constructed. Notably, the flexibility of inkjet 3D printing
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Volume 10 Issue 3 (2024) 65 doi: 10.36922/ijb.2311