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International Journal of Bioprinting Tunable GelMA-based bioinks for keloid modeling

3D-bioprinted constructs. Although higher GelMA content shear-thinning behavior (Figure 3B–C). This increase in
can hinder extrusion due to nozzle clogging, this limitation viscosity reflects alginate’s concentration-dependent chain
can be overcome by co-formulating with alginate, MC, entanglement, which improves printability by supporting
and laponite-RDS to preserve flow characteristics while controlled extrusion and better shape retention. Higher
maintaining structural fidelity. viscosity also enables faster structural recovery post-
printing, a key parameter for high-fidelity bioprinting.
3.2. Alginate as an elasticity enhancer
Both formulations displayed solid-like viscoelastic
In extrusion-based bioprinting, viscosity and shear- characteristics, with storage modulus (Gʹ) consistently
thinning behavior are critical for achieving high-resolution exceeding loss modulus (G˝) over increasing frequencies
structures while maintaining mechanical stability during (Figure 3D). Notably, the Gʹ of the 1% alginate group
and after deposition. Building on previous studies, (G5A1M1R1: 50.17 ± 8.59 Pa) was more than twice that
we investigated the role of alginate as a viscoelasticity of the 0.5% group (G5A0.5M1R1: 19.50 ± 12.52 Pa),
enhancer by comparing formulations containing different suggesting a significant enhancement in network stiffness
alginate concentrations: 0.5% (G5A0.5M1R1) and 1% (Figure 3D–E). This finding supports the role of alginate
(G5A1M1R1), without the use of multivalent cation as a structural modifier that promotes stronger elastic
crosslinkers (Figure 3A). As expected, the bioink with responses within the composite hydrogel. Although the
higher alginate concentration exhibited a substantial increase in G˝ was not statistically significant (Figure 3F),
increase in viscosity (~76%) and more pronounced it followed a similar upward trend.

Figure 3. Role of alginate as a viscoelasticity enhancer. (A) Crosslinked hydrogel blend consists of GelMA (5% w/v), alginate (0.5 and 1% w/v), MC (1%
w/v), and laponite-RDS (1% w/v). Scale bar: 5 mm. (B) Viscosity and (C–G) rheological properties of hydrogel blends with varying alginate concentrations.
(H–I) Mechanical properties with varying concentration of alginate. *p < 0.05, **p < 0.01, ***p < 0.001. (J–K) Printability and shape structural fidelity of
a hydrogel blend. Scale bar: 2.5 mm.

Volume 11 Issue 4 (2025) 452 doi: 10.36922/IJB025160154