Multicolor live-cell chemical imaging by isotopically edited alkyne vibrational palette.
Vibrational imaging such as Raman microscopy is a powerful technique for visualizing a variety of molecules in live cells and tissues with chemical contrast. Going beyond the conventional label-free modality, recent advance of coupling alkyne vibrational tags with stimulated Raman scattering microscopy paves the way for imaging a wide spectrum of alkyne-labeled small biomolecules with superb sensitivity, specificity, resolution, biocompatibility, and minimal perturbation. Unfortunately, the currently available alkyne tag only processes a single vibrational "color", which prohibits multiplex chemical imaging of small molecules in a way that is being routinely practiced in fluorescence microscopy. Herein we develop a three-color vibrational palette of alkyne tags using a (13)C-based isotopic editing strategy. We first synthesized (13)C isotopologues of EdU, a DNA metabolic reporter, by using the newly developed alkyne cross-metathesis reaction. Consistent with theoretical predictions, the mono-(13)C ((13)C≡(12)C) and bis-(13)C ((13)C≡(13)C) labeled alkyne isotopologues display Raman peaks that are red-shifted and spectrally resolved from the originally unlabeled ((12)C≡(12)C) alkynyl probe. We further demonstrated three-color chemical imaging of nascent DNA, RNA, and newly uptaken fatty-acid in live mammalian cells with a simultaneous treatment of three different isotopically edited alkynyl metabolic reporters. The alkyne vibrational palette presented here thus opens up multicolor imaging of small biomolecules, enlightening a new dimension of chemical imaging.
Department of Chemistry, ‡Department of Applied Physics and Applied Mathematics, and §Kavli Institute for Brain Science, Columbia University , New York, New York 10027, United States.
Zhixing
Z
Chen
Daniel W
DW
Paley
Lu
L
Wei
Andrew L
AL
Weisman
Richard A
RA
Friesner
Colin
C
Nuckolls
Wei
W
Min
D000480:Alkynes / Q000737:chemistry*; D003116:Color; D004247:DNA / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure; D005227:Fatty Acids / Q000737:chemistry / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D007202:Indicators and Reagents; D008853:Microscopy / Q000379:methods*; D012313:RNA / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure; D012542:Scattering, Radiation; D013059:Spectrum Analysis, Raman; D014732:Vibration
D000480:Alkynes; D005227:Fatty Acids; D007202:Indicators and Reagents; D012313:RNA; D004247:DNA