title: Infrared surface plasmon resonance: a novel tool for real time sensing of variations in living cells.
abstract: We developed a novel surface plasmon resonance (SPR) method, based on Fourier transform infrared (FTIR) spectroscopy, as a label-free technique for studying dynamic processes occurring within living cells in real time. With this method, the long (micrometer) infrared wavelength produced by the FTIR generates an evanescent wave that penetrates deep into the sample. In this way, it enables increased depth of sensing changes, covering significant portions of the cell-height volumes. HeLa cells cultivated on a gold-coated prism were subjected to acute cholesterol enrichment or depletion using cyclodextrins. Cholesterol insertion into the cell plasma membrane resulted in an exponential shift of the SPR signal toward longer wavelengths over time, whereas cholesterol depletion caused a shift in the opposite direction. Upon application of the inactive analog alpha-cyclodextrin (alpha-CD), the effects were minimal. A similar trend in the SPR signal shifts was observed on a model membrane system. Our data suggest that FTIR-SPR can be implemented as a sensitive technique for monitoring in real time dynamic changes taking place in living cells.
authors.affiliation: Racah Institute of Physics and Department of Cell and Animal Biology, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
authors.forename: Roy
authors.initials: R
authors.lastname: Ziblat
authors.forename: Vladislav
authors.initials: V
authors.lastname: Lirtsman
authors.forename: Dan
authors.initials: D
authors.lastname: Davidov
authors.forename: Benjamin
authors.initials: B
authors.lastname: Aroeti
mesh_terms: D015374:Biosensing Techniques; D002478:Cells, Cultured; D002784:Cholesterol / Q000737:chemistry / Q000378:metabolism; D002942:Circular Dichroism; D003505:Cyclodextrins / Q000737:chemistry; D004563:Electrochemistry / Q000379:methods; D006367:HeLa Cells; D006801:Humans; D008055:Lipids / Q000737:chemistry; D008854:Microscopy, Electron; D010713:Phosphatidylcholines / Q000737:chemistry; D010743:Phospholipids / Q000737:chemistry; D012031:Refractometry; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*; D020349:Surface Plasmon Resonance / Q000379:methods*; D013997:Time Factors; D047391:alpha-Cyclodextrins / Q000737:chemistry
chemical_list: D003505:Cyclodextrins; D008055:Lipids; D010713:Phosphatidylcholines; D010743:Phospholipids; D047391:alpha-Cyclodextrins; D002784:Cholesterol; C028694:1-palmitoyl-2-oleoylphosphatidylcholine; C032613:alpha-cyclodextrin