Cerium-doped bioactive glass-loaded chitosan/polyethylene oxide nanofiber with elevated antibacterial properties as a potential wound dressing

Abstract

In this study, 5 different electrospun chitosan-based scaffolds were fabricated for wound healing applications using benign solvents. Researchers have reported that chitosan/PEO scaffolds are generally unstable in aqueous solutions and have poor mechanical properties particularly in wet conditions, therefore we had to tackle these problems by modifying the scaffolds. The ratio of chitosan to PEO was equal in all of our scaffolds but they contained different amounts of cerium doped bioactive glass (Ce-BG). In a previous study performed by the same authors of this study, the morphology, structure, chemical bonding, cell biocompatibility, and cell cultures of the five scaffolds were analyzed. Meanwhile, the parameters studied in this study were antibacterial activity against gram-positive and gram-negative bacteria cells, mechanical properties, ion release behavior, and swelling properties. Results indicated that although increasing Ce-BG/CH (w/w) ratio up to 20% (w/w) improved the swelling degree and mechanical properties of the scaffolds significantly, increasing the ratio beyond 20% (w/w) reduced the useful effects of Ce-BG on the mentioned properties. The latter phenomenon was probably due to the agglomeration of Ce-BG nanoparticles. Even though the agglomeration of Ce-BG nanoparticles had some adverse effects, it did not affect the antibacterial activity and ion release behavior of the scaffolds. In fact, those properties continued to improve up to a ratio of Ce-BG/CH = 40% (w/w). It is worth noting, however, that increasing the Ce-BG/CH (w/w) ratio to 40% significantly improved the antibacterial activity of the scaffolds against gram-negative E. coli bacteria cells, but not against gram-positive S. aureus. Since none of the as-electrospun scaffolds had satisfactory mechanical properties in wet conditions, a modified sample was fabricated to enhance those properties. The modifications involved coating Ce-BGs nanoparticles with chitosan before inserting them into chitosan-polyethylene oxide electrospinning solutions. In the dried state, the modified sample had a 287% and 889% increase in tensile strength and an 88% and 330% increase in peak strain compared to the unmodified version of the sample and the base scaffold, respectively. Overall, the modified scaffold in its wet state had mechanical properties very close to the skin and its elongation at break was 28.6%, which was only 20% less than the required elongation at break for skin tissue scaffolds.