Raman Imaging of Neoplastic Cells in Suspension

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Raman Imaging of Neoplastic Cells in Suspension
Institut de Ciències Fotòniques Barcelona Spain
www.icfo.es
Caitriona Creely, Sergi Mercadal, Giovanni Volpe,
Marta Soler, and Dmitri V. Petrov
e-mail Giovanni.Volpe_at_icfo.es
San Diego, August 2006
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Why Raman Imaging?
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Optical Tweezers Raman Spectroscopy
Problem How to immobilize cells that live in
suspension? Solution Optical Tweezers
Problem How to detect the biochemical processes
occurring inside the cell? Solution Raman
Spectroscopy
Droplets Lankers et al., Appl. Spectrosc. (1994)
48, 1166 Cellular organelles Ajito and
Torimitsu, Lab on a Chip (2002) 2, 11 Single
cells Xie et al., Opt. Lett. (2002) 27, 249
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Overview
Optical Tweezers Raman Spectroscopy Behaviour
of a cell in an optical trap Raman imaging of
floating cells
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Optical Tweezers Raman Spectroscopy delivers
time-resolved biochemical information
ethanol C2H5OH
glucose
Singh et al., Anal. Chem. (2005) 77, 2564
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Only a small part of the cell is probed... ...and
maybe not always the same part!
1 beam trap
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The light-scattering direction changes over time
Volpe et al., Appl. Phys. Lett. (2006) 88, 231106
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How can we immobilise the cell?
2 beam trap
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Holographic OTRS Setup
Creely et al., Opt. Express (2005) 13, 6105
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Holographic OTRS Setup
adapted from Leach et al., Proc. SPIE (2005)
5736, 37
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Multiple traps stabilise the cell
2 beam trap
1 beam trap
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Polystyrene beads on the surface or floating can
be imaged equally well
Polystyrene 1001 cm-1 peak
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Different chemical components can be imaged in a
neoplastic cell
Jurkat cell transformed human T-cell 8-20
micron diameter
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Unsolved problems
Long acquisition time Lower excitation wavelength
delivers higher Raman signal Cell damage
threshold Depends on the cell under study yeast,
mammalian cell, apoptotic cell, Careful choice
of trapping wavelength Trapping effect of the
Raman laser Counterpropagating configuration
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Review
Optical Tweezers Raman Spectroscopy Behaviour
of a cell in an optical trap Raman imaging of
floating cells
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Acknowledgements

• Dr. T. Thomson, H. Grötsch, and Dr. M. Geli,
• Institute of Molecular Biology, CSIC, Barcelona
  (Spain)
• ESF/PESC (Eurocores on Sons),
• grant 02-PE-SONS-063-NOMSAN
• Spanish Ministry of Education and Science
• Generalitat de Catalunya
• Departament d Universitats, Recerca i Societat
  de la Informació and the European Social Fund

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Raman Imaging of Neoplastic Cells in Suspension
Institut de Ciències Fotòniques Barcelona Spain
www.icfo.es
Caitriona Creely, Sergi Mercadal, Giovanni Volpe,
Marta Soler, and Dmitri V. Petrov
e-mail Giovanni.Volpe_at_icfo.es
San Diego, August 2006