Page 537 - IJB-9-5

International Journal of Bioprinting GelMA/PEG-TA IPN networks for 3D bioprinting

macromer mixture is almost the same as of the 6 wt% and continuous filaments could be extruded through a
GelMA solution and similarly as described above, smooth fine needle (25G) in the temperature window just below
the gel point (Figure S1, Supplementary File). Based on
A B these results, we compared the properties of 6 wt% GelMA
and 6 wt% GelMA/2 wt% 8PEGTA gels.
5
3.4. Gel content and swelling
To determine the swelling of the photo-crosslinked 6
wt% GelMA (GelMA-UV) and 6 wt% GelMA/2 wt%
8PEGTA 5 IPN (GelMA/8PEGTA -IPN) hydrogels,
5
C d macromer solutions were placed in a cylindrical mold at
37°C and cooled to room temperature to give physically
crosslinked networks. Subsequent light exposure
(365 nm) induced photo-crosslinking of the GelMA. In
case of the GelMA/8PEGTA macromer mixture, which
5
also contains HRP (4 U/mL), after UV crosslinking, a
second enzymatically crosslinked network was formed
by incubating the hydrogel in a 0.03 wt% H O solution.
2
2
Figure 3. (A) UV crosslinking kinetics: Storage modulus as a function of UV The gel content and water uptake of the GelMA-UV and
irradiation (375 nm) time of GelMA/8PEGTA at 22°C. (B) Temperature GelMA/8PEGTA -IPN hydrogels are given in Table 1. All
5
5
sweep of the chemically crosslinked GelMA/8PEGTA (2 min UV hydrogels had a gel content higher than 86%. The higher
5
irradiation). (C) Temperature sweep of a 2 wt% 8PEGTA gel formed by
5
enzymatic crosslinking. (D) Storage modulus (G’) and loss modulus (G’’) macromer concentration by addition of 8PEGTA to the
5
of the GelMA/8PEGTA -IPN at 25 and 37°C. GelMA provided a higher crosslinking density, leading to
5

Scheme 3. Top row: Physical and subsequent UV crosslinking of GelMA; middle row: Enzymatic crosslinking of 8PEGTA by HRP in the presence of
5
hydrogen peroxide; bottom row: IPN formation, by consecutive physical and UV crosslinking of the GelMA and enzymatic post-crosslinking, of a mixture
of GelMA, 8PEGTA , and HRP.
5
Volume 9 Issue 5 (2023) 529 https://doi.org/10.18063/ijb.750