Page 254 - IJB-10-1

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

Figure 1. Rheological properties of cellulose microfibrils and guar gum-based inks: (A) apparent viscosity, (B) storage modulus, (C) loss modulus, and
(D) loss factor. Abbreviations: CMF, cellulose microfibril; gg, guar gum; w/,100 mL of 1% (w/v) CMFs.

vibration of carbohydrates, proteins, and polyphenols), without changing the main molecular structure. The
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2900 cm (CH stretching and vibration), 1640 cm CMFs obtained after 160 min of blending had the best
(C=O stretching and vibration, or symmetric bending of physicochemical and structural properties; therefore, it
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CH ), and 1110–1061 cm (stretching C–O–C and C–O was selected for subsequent studies.
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vibrations of carbohydrates). 30,31 Since CMFs are joined by
intra-hydrogen and inter-hydrogen bonds, all the infrared 3.2. Rheological behavior of CMFs/
bands with O–H stretching vibration in the alcoholic guar gum-based ink
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groups appeared in the range of 3600–3000 cm . The Extrudability in 3D printing, which is largely influenced
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band at 1640 cm is due to the bending mode of absorbed by hydrogel’s printability, was indirectly investigated by
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water since the pure cellulose has strong affinity for water, measuring the rheological properties of CMFs-based
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and as a result, the longer blending time lowers the 1640 ink. The hydrogels show shear-thinning behavior, as
cm peak intensity. No new peaks were observed in evidenced by the reduction of apparent viscosity with
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the CMFs produced with different blending treatment increasing shear rate (Figure 1A), suggesting their probable
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times. Therefore, blending could fibrillate cellulose fibers extrudability. The flow parameters of the inks, obtained
Volume 10 Issue 1 (2024) 246 https://doi.org/10.36922/ijb.0164