κ‐Carrageenan Hydrogel Carrier Enhances Drug Bioavailability and Antibacterial Activity of Curcumin‐Functionalized Zinc Oxide Nanoparticles

ABSTRACT This study investigates the impact of curcumin‐adsorbed ZnO nanoparticles (C‐ZnO NPs) on the physical, mechanical, and antibacterial properties of kappa (κ)‐carrageenan hydrogels, focusing on their potential as biocompatible materials. Microstructure analysis revealed that ZnO NPs formed needle‐like structures, providing a large surface area for curcumin adsorption, with an average length of 377.24 nm and a width of 46.09 nm. Functional group analysis indicated successful adsorption of curcumin, a bioactive compound, onto ZnO NPs. Crystallographic analysis showed no significant impact of curcumin on the crystallinity of ZnO NPs. Optical absorbance analysis confirmed the formation of NPs with characteristic absorption peaks. Swelling analysis revealed that κ‐carrageenan hydrogels exhibited a swelling rate of 1987.05 ± 8.28%, while C‐ZnO‐loaded hydrogels showed a comparable swelling rate of 1705.01 ± 2.5%. The water retention capacity analysis indicated that C‐ZnO loaded hydrogels also had a comparable water retention capacity to those without NPs. Mechanical strength tests showed that C‐ZnO‐loaded hydrogels had a significantly higher Young's modulus (0.25353 MPa) compared to κ‐carrageenan hydrogels (0.07157 MPa). Drug release kinetic modeling using the Hixson Crowell and Korsmeyer‐Peppas models best described the release behavior of C‐ZnO from the hydrogels across various pH levels. Cell viability studies showed high viability for both hydrogel types, indicating their potential as biocompatible materials. Antibacterial tests demonstrated the effective bacteriostatic ability of C‐ZnO loaded hydrogels against Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ). These findings highlight the potential of curcumin‐adsorbed ZnO nanoparticles incorporated into κ‐carrageenan hydrogels as multifunctional biomaterials for drug delivery and therapeutic applications.