![]() ![]() When the beating frequency between the pump and Stokes fields (ωp - ωs) is resonant with a Raman-active molecular vibration, four major coherent Raman scattering processes occur simultaneously, namely, coherent anti-Stokes Raman scattering (CARS) at (ωp - ωs) + ωp, coherent Stokes Raman scattering (CSRS) at ωs - (ωp - ωs), stimulated Raman gain (SRG) at ωs, and stimulated Raman loss (SRL) at ωp. In most experiments, coherent Raman processes involve two excitation fields denoted as pump at ωp and Stokes at ωs. With high imaging speed and 3D spatial resolution, coherent Raman scattering microscopy is enabling a new approach for real-time vibrational imaging of single cells in a living system. However, the Raman process is a weak effect, limiting its application for fast chemical imaging of a living system. Vibrational spectroscopy based on spontaneous Raman scattering is widely used for label-free analysis of chemical content in cells and tissues. These challenges highlight a critical need for development of chemical imaging platforms that allow in situ or in vivo analysis of molecules. Fluorescent labels, however, are too bulky for small molecules such as fatty acids, amino acids, and cholesterol. For real-time imaging of labeled molecules in live cells, fluorescence microscopy is the tool of choice. ![]() These tools can indicate the presence of molecules but do not provide information on their location or interaction with each other in real time, restricting our understanding of the functions of the molecule under study. ![]() Taking biochemistry as an example, the majority of our knowledge about cellular content comes from analysis of fixed cells or tissue homogenates using tools such as immunoblotting and liquid chromatography-mass spectrometry. Traditionally, molecules are analyzed in a test tube. ![]()
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |