Chitosan–bacterial nanocellulose nanofibrous structures for potential wound dressing applications
The fabrication of nonwoven mats containing chitosan and bacterial nanocellulose by electrospinning were considered using two different approaches: (1) simultaneous spinning of chitosan and bacterial nanocellulose solutions using two separate syringes towards the same target and (2) coaxial electrospinning, where chitosan and bacterial nanocellulose were simultaneously electrospun through a spinneret composed of two concentric needles to produce core–shell structures. Co-spinning agents were required in both approaches. A direct blend of chitosan and bacterial nanocellulose and subsequent electrospinning was not feasible due to the incompatibility of their respective solvents. The first approach led to the production of mats containing both chitosan and bacterial nanocellulose nanofibers. However, few bacterial nanocellulose fibers were deposited on the collector. Addition of polylactide as a co-spinning agent and an increase in solution temperature (from 22 to 60 °C) during electrospinning was required to improve both fiber formation and collection. On the other hand, coaxial electrospinning showed the best results for the production of nanofibers containing both chitosan and bacterial nanocellulose. Nanofibers with a good yield were obtained by using a chitosan/poly(ethylene oxide) (2.4/0.6 wt/v%) aqueous solution as the inner layer, and a bacterial nanocellulose solution (0.6 wt/v%) as the outer layer. Co-electrospun nanofibers had a diameter of 85 nm in average, and a narrow size distribution. The core/shell nanostructure was validated by transmission electron microscopy whilst energy-dispersive X-ray spectroscopy analysis showed that the nanofibers contained both chitosan and bacterial nanocellulose along their structure. Finally, the mats obtained by the coaxial approach exhibited strong antimicrobial activity with a decrease of 99.9 % of an Escherichia coli population.
KeywordsChitosan Bacterial nanocellulose Electrospinning Antibacterial Wound dressing
The authors thank the Fonds de Recherche du Québec-Nature et Technologies (FRQNT) and the Natural Sciences and Engineering Research Council of Canada (NSERC) for their financial support of this work. The authors would like also to acknowledge Prof. France Daigle from the Department of Microbiology, Infectiology and Immunology, Université de Montréal for her training and support in the antibacterial tests. Finally, the authors thank the reviewers of Cellulose for their valuable comments to improve this manuscript.
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