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International Journal of Bioprinting 3D-printed nanocomposites: Synthesis & applications

Figure 2. Diagrammatic representations of (a) 3D printing standing specimens, (b) S compression illustration, (c) 3D printing lying specimens, and (d) L
compression test. Reproduced with the permission from ref. Copyright © 2017 American Chemical Society.
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efficiency is significantly reduced by phase separation and that most graphene and its derivatives are cytocompatible
graphene agglomeration in the polymer matrix, but this in vitro and in vivo, suggesting their potential in tissue
could be overcome by adding graphene derivatives. 71-75 engineering and regenerative medicine. However,
The use of 3D printing and graphene or its derivatives concentration, geometry, size, and surface functionality
allows rapid prototyping and manufacture of 3D systems of 2D nanomaterials affect biocompatibility. Nanoscale
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with appropriate properties and functionality. In most graphene derivatives, especially tubular ones like single-
cases, printing complex 3D designs with less than 5% walled CNTs (SWCNTs) in the 10–100 nm size range, may
graphene improves their properties, processing time, and cause cytotoxicity and inflammation.
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cost. FDM is an effective way to build complex structures
from graphene-based polymer nanocomposites, according 4.3. Carbon nanotubes/polymer composites
to Wei et al. Guo et al. also reported the creation of an Since the popularization by Iijima, CNTs have been widely
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asymmetrically aligned structure printed with thermoplastic employed to build multifunctional polymer composites
polyurethane (TPU)/graphene composites. The through- because of its outstanding electrical, thermal, and
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plane thermal conductivity of the printed vertically mechanical characteristics. Polymer nanocomposites
aligned framework is shown to be up to 12 W∙m ∙K achieve electrical conduction via inter-aggregate
–1
–1
at 45 wt%. This is approximately eight times higher conductance, field emission, and electron tunneling. Either
than the through-plane thermal conductivity (TC) of a the particles make contact with one another, creating a
laterally printed construct and outperforms several of the conductive effect, or the electrons “tunnel” from one CNT
conventional particulate composite structures (Figure 1g to another, creating a conductive effect. This assembly
and h). Similar kind of phenomenon also has been reported of CNTs results in a percolated network of continuous
elsewhere. Furthermore, Chen et al. discovered that the conductivity. Above a certain critical CNT concentration,
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attributes of the printed structure differed depending on it is feasible to develop a percolated network. Conversely,
printing orientation (Figure 2). The printed structures a quasi-dispersion of CNTs can potentially lead to higher
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are biocompatible with NIH/3T3 fibroblasts, making them electrical conductivity. However, the aggregation of CNTs
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promising tissue engineering scaffolds. Other studies show might clog the nozzles in microextrusion-based printing.
Volume 10 Issue 2 (2024) 86 doi: 10.36922/ijb.1637