Fostering Κ-carrageenan Hydrogels with the Power of Natural Crosslinkers: A Comparison between Tender Coconut Water and Potassium Chloride for Antibacterial Therapy

Hydrogels have emerged as a promising solution to combat infections in various biomedical applications by acting as antibacterial drug carriers, but they lack mechanical strength and must be crosslinked before use. Herein, we investigated whether tender coconut water can be used as a natural alternative to KCl to crosslink κ-carrageenan hydrogels for antibacterial therapy. Κ-carrageenan hydrogels crosslinked with tender coconut water, KCl, and their combination were fabricated, and their morphology, chemical bonding, compressive strength, water uptake capacity, degradation resistance, and cytotoxicity were assessed. The results showed that crosslinking with tender coconut water and KCl increased the compressive strength of κ-carrageenan hydrogels by 450%, rendered an excellent water retention capacity, and degraded by just about 5% after 20 days! The scanning electron micrographs show that crosslinking with tender coconut water and KCl compacted the hydrogel morphology with narrow cracks for efficient diffusion, and such were biocompatible when tested against 3T3 cells. The infrared analysis confirmed that diclofenac sodium remained inert when introduced into the hydrogel matrices. Also, the in-vitro release behavior and antibacterial activity of the hydrogels were assessed by loading them with diclofenac sodium nanoemulsified to increase hydrophilicity, in which the release of the hydrogels crosslinked with tender coconut water and KCl was steady and sustained. Such hydrogels also showed a unique antibacterial activity against Staphylococcus aureus and Escherichia coli, with the latter much more prominent than the former. These results confirm that crosslinking with tender coconut water and KCl is a superior alternative to KCl for κ-carrageenan hydrogels.