Volume 93, Issue 5, 01 March 2003
Index of content:
- APPLIED BIOPHYSICS (PACS 87)
Confocal micro-Raman spectroscopy of single biological cells using optical trapping and shifted excitation difference techniques93(2003); http://dx.doi.org/10.1063/1.1542654View Description Hide Description
We report on the study of single biological cells with a confocal micro-Raman spectroscopysystem that uses optical trapping and shifted excitation Raman difference technique. A tunable diode laser was used to capture a living cell in solution, confine it in the confocal excitation volume, and then excite the Raman scattering. The optical trapping allows us to lift the cell well off the cover plate so that the fluorescence interference from the plate can be effectively reduced. In order to further remove the interference of the fluorescence and stray light from the trapped cell, we employed a shifted excitation Raman difference technique with slightly tuned laser frequencies. With this system, high-quality Raman spectra were obtained from single optically trapped biological cells including E. colibacteria, yeast cells, and red blood cells. A significant difference between control and heat-treated E. coli B cells was observed due to the denaturation of biomolecules.