title: Novel optical nanosensors for probing and imaging live cells.
abstract: This review introduces multifunctional optical nanosensors based on surface-enhanced Raman scattering (SERS) and demonstrates their application in live cells. The novel nanosensors have the potential to improve our understanding of cellular processes on the molecular level. The hybrid sensor consists of gold or silver nanoparticles with an attached reporter species. The sensor can be detected and imaged based on the SERS signature of the reporter. This results in several advantages, such as high spectral specificity, multiplex capabilities, improved contrast, and photostability. SERS sensors not only highlight cellular structures, based on enhanced Raman spectra of intrinsic cellular molecules measured in the local optical fields of the gold nanoparticles, they also provide molecular structural information on their cellular environment. Moreover, the SERS signature of the reporter can deliver information on the local pH value inside a cell at subendosomal resolution. SERS sensors are suitable for one- and two-photon excitation.
  
  
  BACKGROUND
  This review introduces multifunctional optical nanosensors based on surface enhanced Raman scattering (SERS) and demonstrates their application in live cells. These hybrid sensors consist of gold or silver nanoparticles with an attached reporter species. The sensor can be detected and imaged based on the SERS signature of the reporter. SERS sensors highlight cellular structures and provide molecular structural information on their cellular environment. They can also deliver information on the intracellular pH-value at subendosomal resolution.
authors.affiliation: Department of Chemistry, Humboldt University, Berlin, Germany. janina.kneipp@chemie.hu-berlin.de
authors.forename: Janina
authors.initials: J
authors.lastname: Kneipp
authors.forename: Harald
authors.initials: H
authors.lastname: Kneipp
authors.forename: Burghardt
authors.initials: B
authors.lastname: Wittig
authors.forename: Katrin
authors.initials: K
authors.lastname: Kneipp
mesh_terms: D002468:Cell Physiological Phenomena; D008856:Microscopy, Fluorescence / Q000379:methods*; D015336:Molecular Probe Techniques; D049329:Nanostructures / Q000737:chemistry*; D013059:Spectrum Analysis, Raman / Q000379:methods*