Page 260 - IJB-10-1

International Journal of Bioprinting 3D-printed hydrogel with antioxidant activity

Table 2. Textural characteristics of the printed constructs crosslinked with borax
Treatment time (min) Hardness (N) Adhesiveness (mJ) Springiness Cohesiveness
0 1.52 ± 0.06 b 1.42 ± 0.10 a 0.28 ± 0.02 b 0.30 ± 0.01 a
30 73.05 ± 4.60 a 0.15 ± 0.01 b 0.53 ± 0.02 a 0.07 ± 0.01 b
60 73.45 ± 5.87 a 0.35 ± 0.11 b 0.50 ± 0.01 a 0.06 ± 0.00 b
Data are expressed as the means ± standard deviation (n = 3).
The means indicated with different letters within the same column are significantly different at p < 0.05.

sharp peak observed at 1013 cm . Borax is identified by 3.7. pH and ABTS radical scavenging activity of the
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the presence of a broad band at 3341 cm and 1652 cm , crosslinked biomaterials
−1
−1
indicating the existence of H–O–H bending and OH Since CMFs and guar gum were selected to assure
stretching modes as well as the asymmetric stretching of bioavailability of the final printed construct, the feasibility
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the –O bond in BO , identified by the presence of bands at of physiological use of the biomaterial was explored by
3
1442 cm , 1336 cm , and 1252 cm . measuring pH values of the respective substances and
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−1
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composite hydrogel or borax-treated hydrogel (Table S4
The presence of bands at 1125 and 825 cm
−1
suggests the occurrence of asymmetric and symmetric in Supplementary File). pH values of CMF, guar gum, and
borax were around 5.0, 6.3, and 9.5, respectively. As added
stretching of B–O bonds in BO . At 940 cm and guar gum concentration increased from 1% to 7%, the
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4
704 cm , the out-of-plane bending of BO can be pH of the hydrogel increased from 6.0 to 6.4. Also, after
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3
observed. The borax-CMFs-guar gum sample shows a crosslinked by using borax, the pH of borax-CMFs-guar
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narrower range than the guar gum band at 3359 cm , gum sample was around 7.1–7.2. Thus, final biomaterial
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indicating a significant reduction in the broad peak might be physiological, implying that it can be applied as a
of guar gum. This peak slightly shifted toward longer food or biomaterial.
wavelengths, likely due to the absorption of hydroxyl
groups in the galactomannan backbone that formed The antioxidant activity of crosslinked CMFs/guar gum
covalent bonds with borax. A new peak (1338 cm ), gels was investigated. CMFs had no antioxidant activity
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representing B–O infrared absorption of borate esters, while guar gum had (Figure 6). Borax generally showed a
was formed in the borax-CMFs-gum sample, likely due higher antioxidant activity than guar gum. The combined
to the interaction between the monoborate ions present CMFs/guar gum sample had a higher antioxidant activity
in borax and cis-diol groups CMFs. Furthermore, the than guar gum, likely due to an increase in hydroxyl groups
13
absorption band centered around 1661 cm , which following the formation of an interpenetrating network.
−1
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corresponds to H–OH bending, weakened in the borax- The borax-treated CMFs/guar gum samples showed a
CMFs-guar gum sample. 47 significantly higher antioxidant activity than the untreated
The textural properties of the printed constructs, such samples. The monoborate ions present in borax likely
as hardness, adhesiveness, springiness, and cohesiveness formed borate ester complexes by reacting with cis-diol
13
after 12 h storage, showed 1.52 N hardness, 1.42 mJ groups found in CMFs, a component of the hydrogel.
adhesiveness, 0.28 springiness, and 0.30 cohesiveness As a result, borax-treated CMFs/guar gum biomaterial
(Table 2). After crosslinking using borax, the hardness has a good antioxidant property that could be exploited in
and springiness of the construct increased by 40.06 biomedical applications.
and 1.89 folds, respectively, leading to a more ordered 4. Conclusion
conformation with increased mechanical properties and
a high recovery rate of the construct under an applied In this study, a stable 3D construct was at first developed
force. Adhesiveness and cohesiveness were reduced by using CMFs/guar gum-based ink for extrusion-based
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9.47 and 4.29 folds, respectively, suggesting that lesser 3D printing. CMFs showed good thermodynamic
work would be required for the construct to recover to compatibility with guar gum based on morphological,
its original state after the force is removed, indicating structural, thermal, and rheological analysis. The CMFs/
improved mechanical stability. There was no significant guar gum ink demonstrated good extrudability for printing
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difference in the textural profiles of constructs treated for at optimized conditions. The printed biomaterial showed
30 and 60 min. Therefore, to use 1% CMFs/5% guar gum improved mechanical stability, following post-printing
hydrogel as a potential ink, post-printing modification treatment with borax. The treated construct showed
step is essential. good antioxidant properties, suggesting its suitability in
Volume 10 Issue 1 (2024) 252 https://doi.org/10.36922/ijb.0164