Fig. 3

Representative images of S. aureus colonies growing on TSA plates. The load of viable bacteria initially applied to the samples, as well as recovered from the samples, was quantitated based upon the number of bacterial colonies growing on TSA plates after overnight incubation at 37 °C. All samples were plated in duplicate, but only one plate of each duplicate is shown for simplicity of presentation. Samples from dilutions containing bacterial loads which were too high or too low were not plated, as the plates would show nearly confluent growth or no growth. For visual comparison of relative amounts of viable bacteria applied to or recovered from samples, images are aligned vertically according to the fold of serial dilution of bacteria before plating. Digital photographs were also taken of the agar surface with the lid of the plate removed, and those images were used to count the number of colonies using the Colony Counter Plugin of ImageJ (Schneider et al. 2012). a Bacterial colonies obtained from the TSA slurry culture from which the initial load of bacteria was applied to the sample materials. Panels b, c, and d show bacterial colonies recovered from sample materials after a 4 h incubation at 37 °C. Samples are as follows: b aluminum foil backing without nanofibers; c foil-backed 100% acetate nanofibers; d foil-backed acetate nanofibers containing 30% full-spectrum hemp extract. Note the large increase in bacterial growth permitted by the samples of aluminum foil without nanofibers (b) and samples of foil-backed 100% acetate nanofibers (c), as compared to the initial load of bacteria applied (a)