Stimuli-Responsive Graphene Nanohybrids for Biomedical Applications

Figure 12

(a) CFU-counting antibacterial assays against four wild-type (wt) bacterial strains consistently reveal that the PEL-rGO LBL thin film, though barely bactericidal when in the dark, killed >90% airborne bacteria on contact within 10 min upon solar irradiation (AM 1.5 G, at one sun). In contrast, the PEL LBL multilayer barely affected bacterial survival no matter whether solar irradiation was applied or not, similar to the behavior of the bare quartz substrate. Data points are reported as deviation. and indicate and , respectively. (b) Bacterial dead/live viability assays under fluorescence microscopy show that P. aeruginosa and S. aureus cells on a PEL-rGO LBL thin film after 10 min irradiation with a solar simulator (AM 1.5 G) stained intensely red, indicative of dead cells with compromised membranes, whereas those treated similarly but without solar irradiation remained dark in the red channel, indicative of live cells with intact membranes. In striking contrast, cells on a PEL LBL thin film or a quartz substrate remained dark in the red channel in similar assays, no matter whether solar irradiation was applied or not. Scale [125].

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