Fig. 1

The diphenylalanine nanostructures hinder E. coli growth and viability and severely damage bacterial morphology. a Morphology of the nanostructures formed by the studied peptides. Micrographs were obtained via scanning electron microscopy. Scale bar is 10 µm. b Secondary structure of the studied peptides as obtained by circular dichroism (CD). CD spectra were obtained for both of the peptides diluted in ultra-pure water at 25 °C. c Kinetics of the inhibition of bacterial growth. The effect of the diphenylalanine nanostructures and controls on bacterial growth was evaluated by turbidity analysis via absorbance readings at 600 nm of bacteria treated overnight. d Effect of the diphenylalanine nanostructures on bacterial viability. Bacterial viability was evaluated using the Live/Dead backlight bacterial viability kit. Green fluorescence of the Syto9 probe indicates bacterial cells with an intact membrane, while red fluorescence of Propidium Iodide (PI) indicates dead bacterial cells. Scale bar is 50 µm. e Evaluation of the effect of the diphenylalanine nanostructures on bacterial morphology. Micrographs were obtained using a high-resolution scanning electron microscope. Scale bar is 1 µm