Fig. 9. UBI-3, UBI-4 and UBI-10 label bacteria in a concentration dependent manner. (A) UBI-3, UBI-4 and UBI-10 (0.5 μM to 50 μM) co-incubated with methicillin sensitive S. aureus and imaged by confocal microscopy with quantification of fluorescence, demonstrating a concentration dependent increase in bacterial fluorescence. UBI-10 retains a higher fluorescence (per molar equivalents) at all concentrations tested. Right panel shows representative images. (B) Representative images of a co-culture of isolated human neutrophils and methicillin sensitive S. aureus and UBI-10 at 10 μM (upper panels) and at 50 μM (lower panels) demonstrating no labelling of neutrophils at 10 μM, however at 50 μM, occasional neutrophil labelling was observed (blue arrows).