Raman spectroscopy for physiological investigations of tissues and cells

Abstract

Raman micro-spectroscopy provides a convenient non-destructive and location-specific means of probing cellular physiology and tissue physiology at sub-micron length scales. By probing the vibrational signature of molecules and molecular groups, the distribution and metabolic products of small molecules that cannot be labeled with fluorescent dyes can be analyzed. This method works well for molecular concentrations in the micro-molar range and has been demonstrated as a valuable tool for monitoring drug-cell interactions. If the small molecule of interest does not contain groups that would allow for a discrimination against cytoplasmic background signals, "labeling" of the molecule by isotope substitution or by incorporating other unique small groups, e.g. alkynes provides a stable signal even for time-lapse imaging such compounds in living cells. In this review we highlight recent progress in assessing the physiology of cells and tissue by Raman spectroscopy and imaging.

In vitro label‐free screening of chemotherapeutic drugs using Raman microspectroscopy: Towards a new paradigm of spectralomics

“…Vibrational spectroscopy can perform cellular imaging in a (benchtop) microscopic geometry, and can provide non‐invasive label‐free screening of, for example, nanoparticle or drug uptake, trafficking and interaction mechanisms, as well as cellular responses and toxicity , eliminating the need for multiple assays in toxicological screening and drug discovery and preclinical screening stages, by elaborate robotic high‐content analysis systems. Vibrational spectroscopy has also been demonstrated for diagnostic applications, in vivo and ex vivo, in tissue , cells and body fluids . A further potential application which is currently attracting increasing attention is in understanding and screening cellular resistance to therapeutic treatments to guide strategies for personalised therapies .…”

On‐chip spectroscopic assessment of microbial susceptibility to antibiotics within 3.5 hours

“…Among the spectroscopic methods, especially Raman spectroscopy as a label‐free technique which does not require toxic immunochemical staining and reduces sample preparation to a minimum, proved to hold a high potential for fast identification and antibiotic characterization of bacteria . The method is non‐invasive and non‐destructive, which sets it apart from recently accreting mass‐spectrometric approaches ; it instantly delivers a complete molecular fingerprint making the method fast and highly specific, and it can be combined with other techniques to analyze cells . Furthermore, its potential to rapidly detect antibiotic resistances could be demonstrated for vancomycin in enterococci , for penicillin G‐streptomycin and cefazolin in E. coli , for compounds inhibiting β‐lactamase or dihydrofolate reductase enzymes and a panel of 15 antibiotics out of 4 different classes in E. coli , to just name a few.…”

Cellular discrimination using in vitro Raman micro spectroscopy: the role of the nucleolus

“…5,6 Indeed, Raman micro spectroscopy has been shown to provide high specificity and sensitivity, even for pre-cancer detection, [7][8][9][10] and is noninvasive and potentially automatable, thus avoiding the disadvantages of many biomedical techniques used to identify and sort cancerous cells from normal ones, which exhibit low specificity and are destructive or perturb the cellular biology. [11][12][13] As an optical microscopic technique, Raman micro spectroscopy also has the potential to probe the molecular structure on a cellular and subcellular level. 14,15 In comparison to Infrared absorption spectroscopy; Raman micro spectroscopy offers the possibility to study biological matrices in an aqueous environment due to the weak contribution from water.…”