scholarly journals Label-Free Biomedical Imaging with High Sensitivity by Stimulated Raman Scattering Microscopy

Science ◽  
2008 ◽  
Vol 322 (5909) ◽  
pp. 1857-1861 ◽  
Author(s):  
Christian W. Freudiger ◽  
Wei Min ◽  
Brian G. Saar ◽  
Sijia Lu ◽  
Gary R. Holtom ◽  
...  

Label-free chemical contrast is highly desirable in biomedical imaging. Spontaneous Raman microscopy provides specific vibrational signatures of chemical bonds, but is often hindered by low sensitivity. Here we report a three-dimensional multiphoton vibrational imaging technique based on stimulated Raman scattering (SRS). The sensitivity of SRS imaging is significantly greater than that of spontaneous Raman microscopy, which is achieved by implementing high-frequency (megahertz) phase-sensitive detection. SRS microscopy has a major advantage over previous coherent Raman techniques in that it offers background-free and readily interpretable chemical contrast. We show a variety of biomedical applications, such as differentiating distributions of omega-3 fatty acids and saturated lipids in living cells, imaging of brain and skin tissues based on intrinsic lipid contrast, and monitoring drug delivery through the epidermis.

2019 ◽  
Vol 116 (14) ◽  
pp. 6608-6617 ◽  
Author(s):  
Mian Wei ◽  
Lingyan Shi ◽  
Yihui Shen ◽  
Zhilun Zhao ◽  
Asja Guzman ◽  
...  

Three-dimensional visualization of tissue structures using optical microscopy facilitates the understanding of biological functions. However, optical microscopy is limited in tissue penetration due to severe light scattering. Recently, a series of tissue-clearing techniques have emerged to allow significant depth-extension for fluorescence imaging. Inspired by these advances, we develop a volumetric chemical imaging technique that couples Raman-tailored tissue-clearing with stimulated Raman scattering (SRS) microscopy. Compared with the standard SRS, the clearing-enhanced SRS achieves greater than 10-times depth increase. Based on the extracted spatial distribution of proteins and lipids, our method reveals intricate 3D organizations of tumor spheroids, mouse brain tissues, and tumor xenografts. We further develop volumetric phasor analysis of multispectral SRS images for chemically specific clustering and segmentation in 3D. Moreover, going beyond the conventional label-free paradigm, we demonstrate metabolic volumetric chemical imaging, which allows us to simultaneously map out metabolic activities of protein and lipid synthesis in glioblastoma. Together, these results support volumetric chemical imaging as a valuable tool for elucidating comprehensive 3D structures, compositions, and functions in diverse biological contexts, complementing the prevailing volumetric fluorescence microscopy.


2019 ◽  
Vol 205 ◽  
pp. 03003
Author(s):  
Francesco Saltarelli ◽  
Vikas Kumar ◽  
Daniele Viola ◽  
Francesco Crisafi ◽  
Fabrizio Preda ◽  
...  

Stimulated Raman scattering spectroscopy enables label-free molecular identification, but its broadband implementation is technically challenging. We experimentally demonstrate a novel approach to multiplex stimulated Raman scattering based on photonic time stretch. A telecom fiber stretches the broadband femtosecond Stokes pulse after the sample to ∼15ns, mapping its spectrum in time. The signal is sampled through a fast oscilloscope, providing single-shot spectra at 80-kHz rate. We demonstrate high sensitivity in detecting the Raman vibrational modes of various samples over the entire high-frequency C-H stretching region. Our results pave the way to high-speed broadband vibrational imaging for materials science and biophotonics.


2019 ◽  
Author(s):  
Volker Schweikhard ◽  
Andrea Baral ◽  
Vishnu Krishnamachari ◽  
William C. Hay ◽  
Martin Fuhrmann

ABSTRACTThe brains of patients with neurodegenerative diseases such as Alzheimer’s Disease (AD) often exhibit pathological alterations that involve abnormal aggregations of proteins and lipids. Here, we demonstrate that high-resolution, label-free, chemically-specific imaging using Stimulated Raman Scattering Microscopy (SRS) provides novel insights into the biophysical properties and biochemical composition of such pathological structures. In brain slices of a mouse model of AD, SRS reveals large numbers of Amyloid-β plaques that commonly form a characteristic, three-dimensional core-shell structure, with a fibrillar proteinaceous core surrounded by a halo-like shell of lipid-rich deposits. SRS spectroscopic imaging allows for a clean, label-free visualization of the misfolded (β-sheet) Amyloid-β content in the plaque core. Surrounding lipid-rich deposits are found to contain comparatively high concentrations of membrane lipids (sphingomyelin, phosphatidylcholine), but lower levels of cholesterol than healthy white matter structures. Overall, the SRS spectra of plaque-associated lipids closely resemble those of nearby neurites, with the notable difference of a higher degree of lipid unsaturation compared to healthy brain structures. We hypothesize that plaque-associated lipid deposits may result from neuritic dystrophy associated with AD, and that the observed increased levels of unsaturation could help identify the kinds of pathological alterations taking place. Taken together, our results highlight the potential of Stimulated Raman Scattering microscopy to contribute to a deeper understanding of neurodegenerative diseases.


Sensors ◽  
2017 ◽  
Vol 17 (11) ◽  
pp. 2581 ◽  
Author(s):  
Kamel Mars ◽  
De Xing Lioe ◽  
Shoji Kawahito ◽  
Keita Yasutomi ◽  
Keiichiro Kagawa ◽  
...  

2019 ◽  
Vol 63 (5) ◽  
pp. 2028-2034 ◽  
Author(s):  
Kristel Sepp ◽  
Martin Lee ◽  
Marie T. J. Bluntzer ◽  
G. Vignir Helgason ◽  
Alison N. Hulme ◽  
...  

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