Bimetallic hydrogels based on chitosan and carrageenan as promising materials for biological applications

In this study, novel crosslinked hydrogels based on chitosan (CS) and carrageenan (CRG) loaded with silver and/or copper nanoparticles (Ag/CuNPs) were prepared through a freeze-drying (thawing) process to be applied in biological applications comprising wound dressing. These hydrogels showed porous interconnected structures. The influence of the used nanoparticles (NPs) on the antibacterial properties of the CS/CRG hydrogels was explored. Antimicrobial results revealed that both CS/CRG/CuNPs, CS/CRG/AgNPs, and CS/CRG/Ag-CuNPs exhibited promising antibacterial and antifungal activity against Escherichia coli, Pseudomonas aeruginosa, Streptococcus mutans, Staphylococcus aureus, Bacillus subtilis, and Candida albicans. Moreover, CS/CRG/AgNPs, CS/CRG/CuNPs, and CS/CRG/Ag-CuNPs hydrogels showed potential antioxidant activity to be 57%, 78%, and 89%, respectively. Furthermore, cytotoxicity results against Vero normal cell line confirmed that all designed hydrogels are safe upon usage. The bimetallic CS/CRG hydrogels showed notably enhanced antibacterial properties among the as-prepared hydrogels allowing them to be a successful material upon being employed in wound dressing applications.