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Materials Science in Additive Manufacturing Union of 2D nanomaterials and 3D printing

A B

C D

Figure 6. (A–D) A study of three-dimensional graphene microfiber scaffolds with electroactive properties, using microfluidic printing. (A) Schematic
image of the microfluidic 3D printing technology for fabricating 3D graphene electroactive microfibrous scaffolds. (B) SEM images of GO fiber (upper) and
rGO fiber (below), and their magnified images. (C) Live/dead assay images of SH-SY5Y cells cultured on GO microfibrous scaffold and rGO microfibrous
scaffold. (D) SH-SY5Y cell morphology on GO microfibrous scaffold and rGO microfibrous scaffold. Scale bars: B: 100 μm, C and D: 200 μm. The figures
were reproduced from Qing et al. [105] . Copyright 2020, American Chemical Society.
rGO: reduced GO; SEM: Scanning electron microscopy.

electrons on each phosphorus atom within the concave layer. and particle aggregation, which can lead to inhomogeneity
To address this issue, a study was conducted to fabricate a in the material and affect its performance. Nevertheless,
scaffold using the PDA modification method [107] , aiming to Laponite forms a stable and highly conductive network
enhance the stability of BP nanomaterials by modulating of nanoscale platelets that can facilitate the movement of
the surface with suitable tethered organic molecules. PDA, ions and electrons when dispersed in aqueous solutions.
a major component of naturally occurring melanin, offers Tondera et al. utilized poly(3,4-ethylenedioxythiophene)
exceptional biocompatibility and biodegradability [108] . (PEDOT) as a starting material to produce 3D-printed
Coating the nanomaterials’ surfaces with PDA showed neuroprosthetic implants for restoring neurological
improvement in their water dispersibility. In study by Xu functions [109] . PEDOT alone is not sufficient for use in
et al., the researcher found that the hydrogel was able to printed structures due to its insufficient mechanical and
support the growth and differentiation of MSCs, increasing conductive properties, as these structures must be able to
the expression of neural differentiation markers [107] . withstand deformation during body movements, handling,
Furthermore, the hydrogel’s electrical conductivity played and implantation. Laponite and poly(acrylamide)
an important role in promoting neural differentiation, (PAAM) were introduced to address these limitations by
facilitating the communication between the cell. In the providing elasticity, mechanical strength, and improved
in vivo part of the study, the researchers implanted the conductivity. The printed structure containing laponite
BP-incorporated hydrogel into a rat model of spinal cord exhibited plastic deformation and subsequently restored to
injury. The results showed that the hydrogel was able to its original length after strain relaxation until it broke at
promote the regeneration of neural tissue, resulting in 800% tensile strain during tensile strength testing. PEDOT
an improvement in locomotor function, and observed an required doping with an anionic polyelectrolyte, such as
increase in the expression of neural differentiation markers polystyrene sulfonate, to improve its conductivity and
and the growth of new axons, indicating successful neural water dispersion. The PEDOT: laponite–PAAM system’s
regeneration. In conclusion, the BP NPs in the hydrogel remarkable conductivity was attributed to mobile charge
provided a biocompatible and biodegradable platform that carriers’ introduction into the PEDOT backbone, balanced
was able to support the growth and regeneration of neural by negative charges on the laponite crystal surface. This
tissue in vivo. suggests that Laponite played a crucial role in determining
While laponite (nanoclay) does have some desirable the final mechanical and rheological properties of the
properties for use in bioinks and hydrogels, there are system, while also providing excellent electrochemical
limitations to applying it to bioink, such as potential toxicity stability. Overall, doping PEDOT with an anionic

Volume 2 Issue 2 (2023) 12 https://doi.org/10.36922/msam.0620