Page 490 - IJB-9-5

International Journal of Bioprinting CECM-GelMA bioinks of DLP 3D printing for corneal engineering

Figure 3. Physical properties of the GelMA and CECM-GelMA hydrogels. (A) In situ degradation in sample I (time: **, materials: ns); (B) degradation of
collagenase type I (time: ****, materials: ns); (C) kinetic curve of swelling (time: **, materials: **); (D) the degree of swelling and water content (w/w) of the
samples. The data (A–C) were subjected to two-way analysis of variance (ANOVA), and the data (D) were subjected to one-way ANOVA and are expressed
as the mean ± standard deviation (n = 3; * p < 0.05, ** p < 0.01, **** p < 0.0001).

with increasing time. The growth rate was fast in the eye. As shown in Figure 4, the spectral transmittance of
first 2 h, slowed down in 3–4 h, and then reached the the artificial cornea was measured. The transmittance of
swelling equilibrium state, and the swelling degree the prepared composite hydrogel in the visible light range
remained relatively stable. Therefore, the swelling rate of of 400–700 nm showed an increasing trend (Figure 4A).
the composite hydrogel was 476% (Figure 3D). However, In the blue‒violet light waveband, the transmittance was
as shown in Figure 3D, the equilibrium water content of low, which could reduce the damage of radiation to eyes.
the two hydrogels was similar, and there was no significant The transmittance of the sample gradually increased with
difference. Compared with pure GelMA (~85%), the increasing wavelength and remained stable, which was
equilibrium water content of the CECM-GelMA group comparable to the human natural cornea in the relevant
is 82%, which is closer to that of natural corneal (~78%) reference [36,37] . According to Figure 4B, after 2 weeks
tissue. It can help to ensure the stability in the body fluid of culture on the hCF-loaded hydrogel, the spectral
environment. transmittance of the hydrogel was significantly improved
in the range of 700–800 nm. By comparison, with the same
3.3.5. Transmittance sample thickness, the transparency of the CECM-GelMA
The transparency of the cornea is maintained by the hydrogel loaded with cells at 780 nm was 89.36%, while
regular arrangement of collagen fibers and stable corneal without cells, the transmittance was 75.26%. Then, one-
[35]
cells . The cornea allows light with a wavelength of way ANOVA of CECM/GelMA hydrogel samples with
365–2500 nm to pass through, and light with a wavelength and without cells showed a significant difference in p value
below 365 nm has a weaker penetration and is mainly (p = 0.0110). Clearly, the light transmittance of the sample
absorbed by the cornea to prevent UV damage to the changed with the loaded cells.

Volume 9 Issue 5 (2023) 482 https://doi.org/10.18063/ijb.774