Cell experiment:

Microbes and dispersions are mixed and interacted for one hour before being diluted up to 20,000-fold for plating of 0.1 mL of each in triplicate and incubation (24 hours for 37℃) for CFU counting. Cell survival (%), taken as the mean±standard deviation, is plotted against DODAB and/or Gramicidin concentration. As a control for cell viability in the absence of DODAB or DODAB/Gramicidin dispersions, a standard bacterial suspension is added to 0.264 M D-glucose solution, diluted, and spreaded on the agar plate[1].

Gramicidin is an antimicrobial peptide assembling as channels in membranes and increasing their permeability towards cations.

Gramicidin is an antimicrobial peptide assembling as channels in membranes and increasing their permeability towards cations. There is poor Gramicidin activity against E. coli and S. cerevisae as shown from the survival of microbes (%) over a range of Gramicidin concentrations, in contrast with the action of Gramicidin on S. aureus. The microbicidal activity occurs over a range of low Gramicidin and DODAB concentrations which are not toxic to S. cerevisae[1].

[1]. Ragioto DA, et al. Novel gramicidin formulations in cationic lipid as broad-spectrum microbicidal agents. Int J Nanomedicine. 2014 Jun 30;9:3183-92.