Antibacterial activity of zeolitic imidazolate frameworks/bacterial cellulose

This study shows the in situ synthesis and characterization of novel biocompatible hydrogel composites formed by integrating zeolitic imidazolate frameworks (ZIFs) into a bacterial cellulose (BC) matrix. Bacterial cellulose was generated by Lactiplantibacillus plantarum AS.6, followed by the addition of metal salts (Zn²⁺ or Co²⁺), triethylamine, and 2-methylimidazole to promote ZIF crystallization within the BC hydrogel, resulting in the creation of ZIF-8@BC and ZIF-67@BC, respectively. ZIF-8@BC demonstrated particle sizes between 25 and 200 nm, characterized by a porous structure with 100 to 200 nm pore sizes due to the hydrogel strcuture. In contrast, ZIF-67@BC displayed denser crystalline particles and larger pore dimensions of 100 to 650 nm, augmenting hierarchical porosity. Diffuse reflectance spectroscopy (DRS) spectra revealed substantial ultraviolet absorption by ZIF-8@BC and notable visible-light absorption by ZIF-67@BC. Antibacterial experiments targeting Pseudomonas aeruginosa, Escherichia coli, and Salmonella enterica demonstrated notable antimicrobial activity, particularly against P. aeruginosa, with inhibition zones of 35 mm for ZIF-8@BC and 30 mm for ZIF-67@BC. These findings underscore the potential multifunctionality of the hydrogels as antibacterial and optically responsive biomaterials for future biomedical and environmental applications.