Tekleweini Hagos Welemichael

Carbon-based nanomaterials are potentially antimicrobial in water treatment, healthcare and environmental applications. The antibacterial properties of various carbon nanomaterial surfaces have been investigated, however, studies including direct comparisons between carbon nanomaterials with different morphology, chemistry and wettability are few. Moreover, photo-enhanced surface antibacterial activity is not fully understood. Here, we show that simple light emitting diodes (LEDs) can enhance the antibacterial surface activity of three carbon nanomaterials with diverse surface morphology including laser induced graphene (LIG), vertically aligned carbon nanotubes (VACNT), and carbon nanofibers (CNF). Moreover, when hydrophilicity was increased using atmospheric plasma treatment, the LED-activated antibacterial activity of all surfaces was further enhanced. After 40 minutes of exposure to low energy LED light, VACNTs showed the highest bacterial killing activity (93.4%), followed by CNFs (72.5%), and LIG surfaces (69.0%). For plasma-treated surfaces the killing rate was enhanced, and after only 20 minutes of exposure to LED light CNFs surfaces showed 99.1% bacterial killing efficacy, followed by VACNTs (92.6%), LIG (46.1%). Moreover, the antibacterial efficacy of VACNT surfaces increased as the length of the CNTs increased. These findings provide valuable insights in and the roles of various parameters in carbon nanomaterial surfaces in antimicrobial applications.