Page 330 - IJB-10-6

International Journal of Bioprinting 3D-printed PPDO/GO stents for CHD treatment.

the surrounding artery tissues, were isolated to prepare no typical peaks of GO are observed due to the low GO
paraffin sections. The paraffin sections were stained with content. However, the peaks are more distinct as the GO
hematoxylin and eosin (H&E) and anti-CD31 antibody content increases. Results of Raman spectra suggest that
(Servicebio, China). PPDO/GO composite material is successfully prepared.
2.10. Statistical analysis The FT-IR spectra characterize the chemical groups of
Statistical analysis was carried out using SPSS Statistics PPDO, GO, and PPDO/GO materials (Figure 3b and c).
26.0 (IBM, USA). Statistics were expressed as mean ± For pristine PPDO, the sharp and narrow peak at 1732
−1
standard deviation. At least three specimens were tested cm corresponds to the C=O stretching vibration. Peaks
−1
for each experiment in this research. Statistical significance at 1200, 1122, and 1050 cm correspond to the stretching
−1
was analyzed by one-way analysis of variance (ANOVA) vibration of C–O. Peaks at 1429 cm and in the range
−1
with Tukey’s multiple comparison test. A p-value <0.05 was of 2957–2880 cm are attributed to the bending and
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considered to be statistically significant: * p < 0.05, ** p < stretching vibrations of -CH -. For GO, peaks at 1723,
2
−1
0.01, *** p < 0.001. 1385, and 1065 cm correspond to C=O stretching
vibration, C–O–C asymmetric stretching vibration, and
3. Results and discussion C–O stretching vibration, respectively. The peak at 1620
63
cm is ascribed to the aromatic C=C in GO. Figure 3c
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−1
The surface morphology of PPDO/GO films was displays the FT-IR spectra of PPDO/GO materials with the
characterized by SEM (Figure 2a–f). Films fabricated by wavenumber ranging from 3450 to 3000 cm . The broad
−1
solvent casting display a surface morphology consisting of peak at ~3300 cm is attributed to the stretching vibration
−1
densely packed, bubble-like polygonal elements, similar to of hydroxyl groups. With the incorporation of GO, the
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the surface topography of polyhydroxyoctanoate reported peaks become stronger due to the introduction of rich
by Sofińska et al. After the incorporation of GO, the color hydroxyl groups from GO and shift to lower wavenumbers
56
of PPDO/GO films darkens (Figure 2g–l). With increasing as the GO content increases. In the detailed spectra
GO content, aggregates begin to appear on the surface and ranging from 1800 to 1650 cm (Figure S3), the peak
−1
at the junctions of the polygonal elements. For GO contents intensity of carbonyl groups of PPDO is enhanced with the
≤0.5%, almost no aggregates are observed. However, for elevation of GO content. This indicates the formation of
GO contents >0.5%, the number and size of aggregates hydrogen bonds between the hydroxyl groups of GO and
start to increase, and a large number of aggregates can the carbonyl groups of PPDO.
be observed in PPDO/5%GO. This phenomenon may be
caused by the aggregation of GO at higher content levels, The XRD results (Figure 3d) display the characteristic
resulting from hydrogen bonding and strong interlayer peaks of PPDO at 21.9° and 23.8° in all PPDO/GO
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π–π stacking interactions. 57,58 materials. Both PPDO and PPDO/GO materials exhibit
similar XRD patterns regardless of the increase of GO
Raman spectroscopy is a fast and non-destructive content, indicating that the incorporation of GO does not
technique to recognize carbon nanomaterials and affect the crystal structure of PPDO. DSC results (Figure 3e)
characterize their structures in composites with high demonstrate an increase in the degree of crystallinity of
resolution. Raman spectra of PPDO/GO materials PPDO/GO materials with the increase of GO content. GO
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are presented in Figure 3a. Using a 785-nm laser, the acts as a nucleating agent, promoting the heterogeneous
characteristic peaks of PPDO at 1735 and 874 cm are nucleation of PPDO. Some studies have also reported
−1
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observed, corresponding to the C=O symmetric stretching an increase in the degree of crystallinity caused by
vibration of the ester carbonyl group and C–O–C hydrogen bonds. 67,68
symmetric stretching vibration, respectively. Peaks at 1458
and 1050 cm are attributed to -CH - bending vibration As presented in Figure 3f, both PPDO and PPDO/GO
−1
2
and the stretching vibration of C–C of the aliphatic chains, materials exhibit electrical conductivities at the same order
respectively. However, the Raman spectrum of PPDO of magnitude due to the insulative nature of PPDO. At
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exhibits a relatively flat curve under a 532-nm laser, lower levels of GO content, no significant change in the
suggesting no interaction of PPDO with the laser at such electrical conductivity of PPDO/GO materials is observed
a wavelength. However, the characteristic peaks of GO are compared to pristine PPDO. This may be attributed
detected in PPDO/GO materials. The D band at ~1345 cm to the uniform dispersion of GO at a low content. With
−1
and the G band at ~1600 cm correspond to defects and the elevation of GO content, the electrical conductivity
−1
disorders in the carbon lattice and C–C stretching of sp - of PPDO/GO materials increases, as the aggregation of
2
bonded carbon, respectively. In the case of PPDO/1%GO, conductive GO leads to the formation of a local conductive
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Volume 10 Issue 6 (2024) 322 doi: 10.36922/ijb.4530