The impact of bacteria exposure on the plasmonic response of silver nanostructured surfaces.

Paternò G.M., Normani S., Ross A., Pietralunga S., Lanzani G., Scotognella F.
  Lunedì 12/09   14:00 - 19:00   Aula D - Marianna Ciccone   II - Fisica della materia   Presentazione
Silver, in the form of nanostructures, is widely employed as an antimicrobial agent. Despite the large body of work addressing the effects of silver on the antibacterial mechanism and on the (bio)physical chemistry pathways that drive bacterial eradication, little effort has been devoted to the investigation of nanostructured silver plasmon response upon interaction with bacteria. We investigate the bacteria-induced changes of the plasmonic response of silver nanoplates after exposure to the bacterial model $Escherichia coli$ ({E. $coli$). Ultrafast pump-probe measurements indicate that the dramatic changes on particle size/shape and crystallinity, likely stemming from a bacteria-induced oxidative dissolution process, translate into a clear modification of the plasmonic response. Finally, we exploit such an effect to build up photonic crystals embedding silver nanostructures, which have the potential to reveal colorimetrically the presence of bacteria. This study opens innovative avenues in the bio- physics of bio-responsive materials.