Characterisation of morphological, antimicrobial and leaching properties of in situ prepared polyurethane nanofibres doped with silver behenate†
Polyurethane nanofibres in situ doped with silver nanoparticles arising from three different silver precursors as well as zero-valent silver nanoparticles were prepared using free-surface electrospinning with no post-treatment. Throughout the experiment, the best results from all combinations tested were achieved for silver behenate doped nanofibres. These had homogenous nanoparticle coverage (some particles <1 nm in diameter) with uniform fibre morphology (evaluated using extra-high resolution scanning electron microscopy, field emission gun scanning electron microscopy and transmission electron microscopy). Silver behenate doped nanofibres also showed strong antimicrobial properties against Escherichia coli, displaying growth inhibition levels of >99% as well as inhibition zones of 1.20 ± 0.12 mm for E. coli, 1.45 ± 0.08 mm for Staphylococcus aureus and 0.62 ± 0.12 mm for Pseudomonas aeruginosa at concentrations corresponding to 1 McFarland. Moreover, after 168 h, silver behenate doped nanofibres displayed the lowest silver leaching (5.8% of original silver content) of all samples prepared in this study. These nanofibres, therefore, represent a promising alternative to current silver-doped nanofibres prepared in situ.