In Situ Monitoring of the "Point Discharge" Induced Antibacterial Process by the Onsite Formation of a Raman Probe

Anal Chem. 2020 Jan 21;92(2):2323-2330. doi: 10.1021/acs.analchem.9b05265. Epub 2020 Jan 7.

Abstract

Electroporation induced by the "point discharge" effect is an effective technique for bacteria inactivation. Rapidly monitoring the electroporation-induced inactivation process is important for screening nanomaterials with high antimicrobial performance. In this study, we develop a facile strategy to in situ monitor the electroporation induced antimicrobial mechanism based on the surface-enhanced Raman scattering (SERS) effect of the Au-nanotip arrays. Owning to the high local-electric field (∼107 V m-1) generated on the Au nanotips, the bacteria are rapidly electroporated and effectively inactivated with ≥99.9% reduction in bacteria colony counts by only applying an external voltage of +0.8 V for 10 s. The related inactivation mechanism is directly verified by the formation of the Prussian blue (PB) nanocrystals by leaking of the uptaken [Fe(CN)6]3- ions from the cleavage area on the cell membrane. These [Fe(CN)6]3- ions react with Fe2+ to form PB nanocrystals onsite as soon as they leak out. The characteristic peak of PB in the cellular Raman-silent region provides a collective monitoring approach for the destruction of microorganisms. The present strategy not only develops a facial method for future use in evaluating electroporation materials, but also paves a rapid way for offering accurate information on some antibacterial and antitumor processes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / chemistry
  • Anti-Bacterial Agents / pharmacology*
  • Escherichia coli / drug effects*
  • Ferrocyanides / chemistry
  • Ferrocyanides / pharmacology*
  • Microbial Sensitivity Tests
  • Nanoparticles / chemistry*
  • Particle Size
  • Spectrum Analysis, Raman
  • Staphylococcus aureus / drug effects*
  • Surface Properties

Substances

  • Anti-Bacterial Agents
  • Ferrocyanides
  • ferric ferrocyanide