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International Journal of Bioprinting Dual ions mixed GelMA for hair follicle regeneration

Figure 4. Characterization of hydrogels. (A) SEM images of GelMA and GelMA-Zn/Si hydrogels. (B, C) Comparison of the pore size and porosity of
hydrogels. (D) Comparison of the swelling ratio of GelMA and GelMA-Zn/Si hydrogels. (E) Degradation of the GelMA and GelMA-Zn/Si hydrogels.
(F) Typical images of the compression test process. (G) Typical compression stress–strain curves of the hydrogels. (H) The compressive modulus (15%–
25% strain pressure) of different hydrogels. (I) G′ and G″ at an angular frequency of 1 Hz at 25°C. (J) Apparent viscosities of hydrogels under steady
−1
−1
shear from 0.1 s to 100 s at 25°C. (K) G′ and G″ under steady angular frequency from 0.1 rad/s to 100 rad/s and an oscillatory strain of 5% at 25°C. (L)
GelMA-Zn/Si hydrogel can release biologically active ions within 7 days. *P < 0.05, ***P < 0.001. N = 3 for each group. All the analyses in (B), (C), (D), and
(H) were performed with an unpaired two-tailed t-test. The analyses in (E) were performed with two-way ANOVA.

3.6. Histological analysis group, GelMA-Zn/Si hydrogel group had a larger number
To further confirm hair follicle regeneration in GelMA- of K19 cells, indicating that hair follicle-related cells
+
Zn/Si hydrogel group, H&E staining was performed on began to migrate and neogenic hair follicles started to
the samples. On the 14th day, GelMA-Zn/Si hydrogel grow (Figure 6B and C). In contrast, the control group had
group had the most hair follicles whereas the other groups nearly no K19-positive staining. The results suggested that
nearly have no regeneration tendency (Figure 6A). Then, GelMA-Zn/Si hydrogel can activate HFSCs to promote
immunofluorescence staining was performed to observe hair follicle regeneration.
HFSC marker K19 . After treatment with GelMA-Zn/ Vascularization of the wound areas is important to
[29]
Si hydrogel, the activation of HFSCs in the wound was wound repair and tissue regeneration . To observe the
[30]
determined. As compared with GelMA and hydrocolloid vessel regeneration, CD31 and α-SMA were stained in

Volume 9 Issue 3 (2023) 207 https://doi.org/10.18063/ijb.703