Preparation of Ultrafine Poly(ethylene oxide)/Poly(ethylene glycol) Fibers Containing Silver Nanoparticles as Antibacterial Coating

Poly(ethylene oxide) (PEO) solutions containing various amounts of poly(ethylene glycol) (PEG) and various amount of silver (Ag) nanoparticles were prepared. The occurrence of Ag nanoparticles was by a direct reduction of Ag+ ions from the addition of silver nitrate (AgNO₃) of varying amount (0.5-2.5%) in the PEO 5%/PEG (2 and 35 kDa) 1-15% solutions. The average diameter of the Ag nanoparticles was found to increase with increasing the PEG molar mass and with decreasing PEG concentration. Electrospinning of the PEO/PEG solutions was relatively easy. Beaded fibers were observed from the PEO solutions that contained 1 and 5% PEG 2 kDa and 1% PEG 35 kDa. Other than these, only smooth fibers were observed. The average diameters of the as-spun fibers were generally found to increase with increasing concentration and molar mass of PEG and increasing amount of added AgNO₃. The amount of the elemental Ag observed was found to increase with increasing PEG content and increasing amount of AgNO₃ added and the amount of the elemental Ag was also found to be greater when the PEG with the lower molar mass was used as the reducing agent. Lastly, the assessment for the antimicrobial activity of the PEO 5%/PEG 15% solutions containing 0.5-2.5% AgNO₃ against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli (E. coli) showed that the antibacterial activity of these solutions was found to increase with increasing AgNO₃ content and the as-formed Ag nanoparticles were found to be more effective in the protection against E. coli.