Raman molecular imaging of cells and tissues: towards functional diagnostic imaging without labeling.

Raman spectroscopy has long been used as a powerful tool for chemical composition analyses. Raman scattering light measurement has the advantage of being able to examine biomolecules in a nondestructive and non-labeling manner. However, molecular imaging of cells and tissues by using Raman microscopy had been hampered due to weak Raman signals and required long acquisition time. Recent advances in imaging devices, such as development of slitscanning Raman microscopy, have enabled us to acquire high-resolution Raman images of biomedical samples. Thus, Raman molecular imaging now has wide application potential for in-situ functional analysis of biomolecules in living bodies, such as studies of intracellular drug pharmacokinetics and oxygen saturation of blood capillaries. There is a possibility that Raman scattering light measurement can be applied for functional diagnostic imaging of human bodies, taking advantage of its noninvasive merits in the future. This review briefly highlights recent topics in spontaneous Raman molecular imaging of cells and tissues.