High Water Content Physically Cross-linked Hybrid Hydrogels Based on Polyester Dendrimers and Cellulose Nanofibrils: A Comprehensive Study
Faridah Namata, Natalia Sanz del Olmo, Lars Wågberg, Michael Malkoch
Abstract
High Resolution Image Download MS PowerPoint Slide Structurally perfect cationic polyester dendrimers based on 2,2 dimethylolpropionic acid (bis-MPA) were exploited in combination with anionic cellulose nanofibrils (CNFs) in the fabrication of a comprehensive library of electrostatically cross-linked hybrid hydrogels. Three distinct families of cationic bis-MPA dendrimers ranging from first to third generation were used, displaying up to 24 peripheral ammonium groups. The dendrimer families covering different hydrolytic stability and peripheral ammonium groups, β-alanine, cysteamine hydrochloride, and N, N -dimethylcysteamine hydrochloride were chosen as ammonium groups. The self-assembly process occurred spontaneously without external stimuli, resulting in well-organized and self-supporting hydrogels. The water content of the hydrogels reached values up to 99.6 wt % with a storage modulus ranging from 1.2 to 3.0 kPa which is within the range of skin tissue. The antibacterial activity of the dendrimers and the formed hydrogels was evaluated against Gram-negative and Gram-positive bacteria strains, and the cytotoxicity was determined by measured cell viability prevention of diverse cell lines. The hydrogels based on TMP-G1-[Cys] 6 exhibited the highest antibacterial activity without showcasing toxicity. To demonstrate its effectiveness, the hydrogel was freeze-dried, resulting in a porous aerogel that exhibited significantly greater antibacterial activity than commercially available band-aids.