Exploring CARS microscopy as a tool for drug discovery

Lead Research Organisation: Cardiff University
Department Name: School of Biosciences


Optical microscopy is an indispensable tool in cell biology and is still the only practical way to decipher the cellular location, function and interactions of biomolecules and small molecular compounds in living cells with high spatial and temporal resolution. Advances within the field of optical microscopy technologies have enabled a new generation of microscopes to be developed that allow the chemical components of a cell to be visualised without the need of staining or manipulation. Coherent anti-Stokes Raman scattering (CARS), combines the chemical specificity of Raman spectroscopy with the intrinsic optical sectioning of multiphoton microscopy. In recent years, CARS has emerged as the label-free multiphoton micro-spectroscopy technique with high potential in biology-related applications. Beyond single-frequency CARS, the true potential of CARS is when measuring a broad vibrational spectrum which enables us to quantify the full chemical composition of biological systems in a non-invasive manner.

Towards this aim we have developed a multimodal multiphoton laser-scanning microscope for cell imaging featuring simultaneous acquisition of CARS, two-photon fluorescence (TPF) and second harmonic generation (SHG) using a single broadband laser (Pope et al 2012, Pope et al 2013). Alongside this hardware development, we have pioneered a data analysis algorithm in order to extract quantitative information on the spatial distribution and absolute concentration of chemical components following hyperspectral CARS imaging (Masia et al 2013, Masia et al 2014).

This collaborative project between Cardiff University and GSK will explore and develop the high throughput potential for CARS microscopy as a screening system for multiplexed assays, delivering high content information following application of small molecules and biotherapeutics of interest. We will explore whether unique spectra can be associated with a range of cellular phenotypes important in drug screening such as early stage apoptosis, necrosis, toxicity and autophagy and define the ability of CARS to identify these cellular phenotypes. CARS will also be exploited to provide a number of parameters that can be gathered without subsequent labelling or imaging (nuclear content, size and shape, cell size and shape, lipid content, cell number) for assessment of cell growth and viability.


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Studentship Projects

Project Reference Relationship Related To Start End Student Name
BB/N50371X/1 01/10/2015 30/09/2019
1646439 Studentship BB/N50371X/1 01/10/2015 30/09/2019 Dale Boorman
Description Through labelling with the heavier isotope of hydrogen, deuterium, biological or chemical molecules (e.g. drug compounds) can be visualised inside cells using our multimodal CARS system at Cardiff. This has enabled us to study distribution, accumulation and turnover of various biological and chemical components without the necessity for fluorescent labelling. We have investigated cellular metabolism, in particular storage and turnover of lipids into droplets, as well as potential accumulation sites of some chemical compounds which could be indicative of drug-induced cellular and systemic effects.
Exploitation Route We have achieved varied degrees of success when visualising different biological and chemical molecules, which can be attributed to a combination of the number of deuterium atoms which the molecule contains and the extent to which the molecule concentrates within a given volume. Thus, further research is warranted to either improve the sensitivity of the CARS imaging system or to enable synthesis of deuterium-containing molecules de novo, which would allow a great deal of flexibility to investigate the relationship between degree of deuterium labelling and the achieved signal-to-noise.
Sectors Chemicals,Healthcare,Pharmaceuticals and Medical Biotechnology