Electrospun cellulose acetate fibers containing chlorhexidine as a bactericide

Submicron fibers with bactericidal properties were prepared from electrospinning of blends containing cellulose acetate (CA) as a polymer base, chlorhexidine (CHX) as a bactericidal agent, and organic titanate Tyzor® TE (TTE) as a cross-linker. A small amount of high molecular weight poly(ethylene oxide) (PEO) was incorporated into the blends to facilitate the electrospinning, and its effect on the extensional properties and spinnability of the N,N-dimethylformamide (DMF) solutions were evaluated. The CHX-containing fiber meshes were cured by TTE in the presence of water vapor, which created covalent links between the CA and CHX. The immobilization of CHX on or within the fibers was confirmed by FTIR, Raman and XPS measurements. The resulting fiber meshes exhibited bactericidal properties on contact, due to the CHX immobilized on the fibers, and within a zone of inhibition (ZoI), due to the release of unbound CHX. The relationship of ZoI for the gram-negative Escherichia coli and the gram-positive Staphylococcus epidermidis to the amount of unbound CHX in the fibers is described by a simple diffusion model. The contact bactericidal capacity against both E. coli and S. epidermidis was assayed after complete removal of unbound CHX from the fibers. A post-spin treatment to attach CHX onto CA–PEO fibers via TTE linkers was also shown to be effective.