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Label‐Free Live‐Cell Imaging of Nucleic Acids Using Stimulated Raman Scattering Microscopy
Author(s) -
Zhang Xu,
Roeffaers Maarten B. J.,
Basu Srinjan,
Daniele Joseph R.,
Fu Dan,
Freudiger Christian W.,
Holtom Gary R.,
Xie X. Sunney
Publication year - 2012
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201100890
Subject(s) - raman scattering , microscopy , raman spectroscopy , nucleic acid , chemical imaging , coherent anti stokes raman spectroscopy , signal (programming language) , chemistry , optics , biophysics , physics , biology , hyperspectral imaging , biochemistry , remote sensing , computer science , programming language , geology
Imaging of nucleic acids is important for studying cellular processes such as cell division and apoptosis. A noninvasive label‐free technique is attractive. Raman spectroscopy provides rich chemical information based on specific vibrational peaks. However, the signal from spontaneous Raman scattering is weak and long integration times are required, which drastically limits the imaging speed when used for microscopy. Coherent Raman scattering techniques, comprising coherent anti‐Stokes Raman scattering (CARS) and stimulated Raman scattering (SRS) microscopy, overcome this problem by enhancing the signal level by up to five orders of magnitude. CARS microscopy suffers from a nonresonant background signal, which distorts Raman spectra and limits sensitivity. This makes CARS imaging of weak transitions in spectrally congested regions challenging. This is especially the case in the fingerprint region, where nucleic acids show characteristic peaks. The recently developed SRS microscopy is free from these limitations; excitation spectra are identical to those of spontaneous Raman and sensitivity is close to shot‐noise limited. Herein we demonstrate the use of SRS imaging in the fingerprint region to map the distribution of nucleic acids in addition to proteins and lipids in single salivary gland cells of Drosophila larvae, and in single mammalian cells. This allows the imaging of DNA condensation associated with cell division and opens up possibilities of imaging such processes in vivo.