Page 14 - IJB-9-6

International Journal of Bioprinting Electrospinning PETG

Table 1. Average fiber diameter based on the solvent split The crystallinity of PETG can be seen from the 1116 cm
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(C–O stretching) as it is slightly shifted to the right and
Solution (DCM/TFA) (% v/v) Fiber diameter (µm) exhibits shoulder band at ~1190 cm . In addition, the peak
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85/15 1.108 ± 0.181 at 1727 cm appears wider for lower crystalline materials.
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70/30 0.800 ± 0.1307 Both phenomena were observed in DCM dominant solvent
60/40 0.677 ± 0.221 splits, which were lower in crystallinity .
[34]
50/50 0.559 ± 0.162
40/60 0.428 ± 0.084 3.4. Inoculation
The bioactivity of produced meshes was assessed using
30/70 0.289 ± 0.079 spore inoculation. After inoculating the meshes with
15/85 0.243 ± 0.100 yellow rust spores, they were placed in the incubator for
24 h. The meshes were then removed from the incubator
of the solvents, as TFA is more volatile than DCM, which and inspected to assess its bioactivity. Figure 6A presents
causes rapid evaporation that leads to thinner fibers. the SEM image at 0 h where the spores are shown to be

3.3. Mesh composition dispersed on the meshes. Figure 6B shows the clusters
The chemical composition of the electrospun PETG meshes growth of the fungal spores after 24 h. Figure 6C and D
was investigated using FTIR, a non-destructive analytical present magnified images of the germinated germ tubes,
technique that allows to qualitatively assess the crystallinity proving the bioactivity of the produced meshes that
of the electrospun meshes. Figure 4 shows the FTIR spectra encourages the growth of fungal spores. This proves that
for the different electrospun meshes. Common PETG the produced meshes are bioactive, enabling the growth of
characteristic peaks were recorded at 965 cm (C–H the fungal spores.
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stretching peak of cyclohexylene ring) , 1106 cm (in-
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[31]
plane vibrations of the C–H bonds) , 1260 cm (ester 4. Conclusion
[31]
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groups) , 1717 cm (C=O ester group) , 2861 cm and In this study, we investigated strategies to create PETG
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[31]
[31]
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2939 cm (C–H symmetrical and asymmetrical stretching electrospinning meshes, a polymeric material that is
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vibration in the aliphatic polymeric chains) . difficult to spin. To the best of our knowledge, this was
[31]
As the C–H stretching of cyclohexene ring increases, the first attempt to create PETG meshes using solution
it can be concluded that the cyclohexanedimethanol electrospinning. Multiple single and binary solvent systems
(CHDM; amorphous material) content also increases and were used to investigate the solubility of PETG, and it
[23]
crystallinity decreases . Moreover, from the different was found that DCM/TFA presented the best solubility–
solvent splits, it can be noted that the TFA dominant splits spinnability results among the different solvents. Optimal
have a slightly higher crystallinity compared to DCM processing conditions were determined, and final meshes
dominant splits. were produced at a flow rate of 4 mm/h, a voltage of
16 kV, and a humidity of 40%–50%. Meshes obtained
Raman spectroscopy was used as a non-destructive, under optimal processing conditions were chemically
robust, and rapid analytical technique to qualitatively assess characterized using both FTIR and Raman spectroscopy,
the chemical difference between different electrospun and the results showed that meshes produced using
meshes. The results are presented in Figure 5. All obtained DCM dominant splits have lower crystallinity, where
spectra were treated with baseline correction by subtracting meshes produced using TFA dominant splits have higher
a polynomial fit of the baseline from the raw spectra. This crystallinity. This can be attributed to the difference
was done to remove the tilted baseline variation occurring in volatility and evaporation rate of DCM and TFA.
due to different noises. Morphological characterization was performed using
Common PETG characteristic peaks were obtained SEM and the results showed the presence of beads in
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at 793 cm (C–H ring out-of-plane bending + C = O TFA dominant splits, whereas DCM dominant splits were
bending) , 900 cm (C–H ring out-of-plane-bending) , bead-free. Moreover, meshes produced using DCM/TFA
[32]
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[32]
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[32]
1021 cm (C–H ring in-plane bending) , 1116 cm (1:1) presents the best trade-off between fiber thickness
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[32]
(C–O stretching) , 1273 cm (C–O stretching of ester and surface roughness. Inoculation on the optimal mesh
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[32]
[32]
group) , 1377 cm (gauche CH wagging) , 1502 cm was carried, to investigate the bioactivity, and the results
2
(-CH bending peak of the PETG macromolecular chain demonstrated fungal germination and proliferation of the
2
backbone) , 1613 cm (symmetric stretching of the 1,4 yellow rust spores on these meshes. Our results suggest
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[32]
para di-substituted benzene ring) , and 1727 cm (C = O that the produced electrospun PETG meshes have high
[33]
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[32]
stretching of ester group) . potential to be used in sensing applications.
Volume 9 Issue 6 (2023) 6 https://doi.org/10.36922/ijb.0024