3D-Bioprinted Hydrogels Based on Calcium Alginate and Turmeric ( <i>Curcuma longa</i> L.): Comprehensive Structural, Functional, and Biological Evaluation for Advanced Wound Healing Applications

Sodium alginate polysaccharide is widely used for its ability to form hydrogels in the presence of calcium ions, showing excellent liquid retention properties. At the same time, Curcuma longa L. (CR) is known for its anti-inflammatory, antioxidant, and antimicrobial activities. Considering these characteristics, this study aimed to develop hydrogels from the combination of calcium alginate (CA) and CR through 3D bioprinting. The samples were characterized for their structural, spectroscopic, morphological, hydrophilic, thermal, and biological properties. UV–Vis spectroscopy monitored CR release, fitting to classical kinetic models. The release profile was concentration-dependent, where the 1.0% (w/v) CR hydrogel exhibited a faster and higher release while the 0.5% (w/v) CR formulation provided a slower and more controlled release. Kinetic modeling demonstrated that the Korsmeyer–Peppas model provided the best fit (R2 > 0.99), with release exponents (n ≈ 0.50–0.54) consistent with Fickian to anomalous diffusion. The Higuchi model also correlated well (R2 ≈ 0.86–0.89), reinforcing a diffusion-driven release mechanism. Biological assays revealed that 1.0% (w/v) CR hydrogels exhibited significant antibacterial activity against Staphylococcus aureus, with inhibition halos up to 12.67 mm but showed cytotoxicity to L929 fibroblasts (35% viability). In contrast, the 0.5% (w/v) CR hydrogel maintained biocompatibility (80% viability) while enabling sustained release of CR. Altogether, these findings highlight the versatility of CA/CR hydrogels, which combine swelling capacity, thermal stability, and controlled release of CR. Such systems are promising as advanced wound dressings, addressing the challenge of balancing antimicrobial efficacy with cellular biocompatibility. Future studies should include in vivo validation and testing under simulated chronic wound conditions to confirm their long-term safety and therapeutic potential.