Quantitative chemical imaging with multiplex stimulated Raman scattering microscopy.
Stimulated Raman scattering (SRS) microscopy is a newly developed label-free chemical imaging technique that overcomes the speed limitation of confocal Raman microscopy while avoiding the nonresonant background problem of coherent anti-Stokes Raman scattering (CARS) microscopy. Previous demonstrations have been limited to single Raman band measurements. We present a novel modulation multiplexing approach that allows real-time detection of multiple species using the fast Fourier transform. We demonstrate the quantitative determination of chemical concentrations in a ternary mixture. Furthermore, two imaging applications are pursued: (1) quantitative determination of oil content as well as pigment and protein concentration in microalgae cultures; and (2) 3D high-resolution imaging of blood, lipids, and protein distribution in ex vivo mouse skin tissue. We believe that quantitative multiplex SRS uniquely combines the advantage of fast label-free imaging with the fingerprinting capability of Raman spectroscopy and enables numerous applications in lipid biology as well as biomedical imaging.
Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
Dan
D
Fu
Fa-Ke
FK
Lu
Xu
X
Zhang
Christian
C
Freudiger
Douglas R
DR
Pernik
Gary
G
Holtom
Xiaoliang Sunney
XS
Xie
D000818:Animals; D000460:Chlorophyta / Q000166:cytology; D008055:Lipids / Q000737:chemistry*; D051379:Mice; D058086:Microalgae / Q000737:chemistry / Q000166:cytology; D011506:Proteins / Q000737:chemistry*; D012867:Skin / Q000737:chemistry; D013059:Spectrum Analysis, Raman / Q000295:instrumentation / Q000379:methods*
D008055:Lipids; D011506:Proteins