Triclosan loaded electrospun nanofibers based on a cyclodextrin polymer and chitosan polyelectrolyte complex

This work focuses on the relevance of antibacterial nanofibers based on a polyelectrolyte complex formed between positively charged chitosan (CHT) and an anionic hydroxypropyl betacyclodextrin (CD)-citric acid polymer (PCD) complexing triclosan (TCL). The study of PCD/TCL inclusion complex and its release in dynamic conditions, a cytocompatibility study, and finally the antibacterial activity assessment were studied. The fibers were obtained by electrospinning a solution containing chitosan mixed with PCD/TCL inclusion complex. CHT/TCL and CHT-CD/TCL were also prepared as control samples. The TCL loaded nanofibers were analyzed by Scanning Electron Microscopy (SEM), Fourier Transformed Infrared spectroscopy (FTIR) and X-Ray Diffraction (XRD). Nanofibers stability and swelling behavior in aqueous medium were pH and CHT:PCD weight ratio dependent. Such results confirmed that CHT and PCD interacted through ionic interactions, forming a polyelectrolyte complex. A high PCD content in addition to a thermal post treatment at 90 °C were necessary to reach a nanofibers stability during 15 days in soft acidic conditions, at pH = 5.5. In dynamic conditions (USP IV system), a prolonged release of TCL with a reduced burst effect was observed on CHT-PCD polyelectrolyte complex based fibers compared to CHT-CD nanofibers. These results were confirmed by a microbiology study showing prolonged antibacterial activity of the nanofibers against Escherichia coli and Staphylococcus aureus. Such results could be explained by the fact that the stability of the polyelectrolyte CHT-PCD complex in the nanofibers matrix prevented the diffusion of the PCD/triclosan inclusion complex in the supernatant, on the contrary of the similar system including cyclodextrin in its monomeric form.

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