title: Label-Free in Situ Discrimination of Live and Dead Bacteria by Surface-Enhanced Raman Scattering.
abstract: Techniques to distinguish between live and dead bacteria in a quantitative manner are in high demand in numerous fields including medical care, food safety, and public security as well as basic science research. This work demonstrates new nanostructures (silver nanoparticles coating bacteria structure, Bacteria@AgNPs) and their utility for rapid counting of live and dead bacteria by surface-enhanced Raman scattering (SERS). We found that suspensions containing Gram-negative organisms as well as AgNPs give strong SERS signals of live bacteria when generated selectively on the particle surface. However, almost no SERS signals can be detected from Bacteria@AgNPs suspensions containing dead bacteria. We demonstrate successful quantification of different percentages of dead bacteria both in bulk liquid and on glass surfaces by using SERS mapping on a single cell basis. Furthermore, different chemicals have been used to elucidate the mechanism involved in this observation. Finally, we used the Bacteria@AgNPs method to detect antibiotic resistance of E. coli strains against several antibiotics used in human medicine.
authors.affiliation: †Chair for Analytical Chemistry, Technische Universität München, Marchioninistr. 17, D-81377 Munich, Germany.
authors.forename: Haibo
authors.initials: H
authors.lastname: Zhou
authors.affiliation: †Chair for Analytical Chemistry, Technische Universität München, Marchioninistr. 17, D-81377 Munich, Germany.
authors.forename: Danting
authors.initials: D
authors.lastname: Yang
authors.affiliation: †Chair for Analytical Chemistry, Technische Universität München, Marchioninistr. 17, D-81377 Munich, Germany.
authors.forename: Natalia P
authors.initials: NP
authors.lastname: Ivleva
authors.affiliation: †Chair for Analytical Chemistry, Technische Universität München, Marchioninistr. 17, D-81377 Munich, Germany.
authors.forename: Nicoleta E
authors.initials: NE
authors.lastname: Mircescu
authors.affiliation: ‡Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie, Ludwig-Maximilians-University, Marchioninistr. 17, D-81377 Munich, Germany.
authors.forename: Sören
authors.initials: S
authors.lastname: Schubert
authors.affiliation: †Chair for Analytical Chemistry, Technische Universität München, Marchioninistr. 17, D-81377 Munich, Germany.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Niessner
authors.affiliation: ‡Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie, Ludwig-Maximilians-University, Marchioninistr. 17, D-81377 Munich, Germany.|§Division of Infectious Diseases and Tropical Medicine, Medical Centre of the University of Munich (LMU), Leopoldstrasse 5, 80802 Munich, Germany.|⊥German Centre for Infection Research (DZIF), partner site Munich, Leopoldstrasse 5, 80802 München (Munich), Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Wieser
authors.affiliation: †Chair for Analytical Chemistry, Technische Universität München, Marchioninistr. 17, D-81377 Munich, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Haisch
mesh_terms: D001419:Bacteria / Q000302:isolation & purification*; D053768:Metal Nanoparticles; D046529:Microscopy, Electron, Transmission; D012834:Silver / Q000737:chemistry; D013059:Spectrum Analysis, Raman / Q000379:methods*
chemical_list: D012834:Silver