Raman Microscopy
Biomedical Engineering
Cancer Detection • Drug Development
Raman Spectroscopy for Cancer Diagnosis
Near-infrared Raman spectroscopy is being developed at Southwest Research Institute (SwRI) to provide a diagnosis tool for early cancer detection.
A comparison of the average Raman spectrum of the normal (blue line) and ApcMin mouse (red line) jejunum tissue. ApcMin mouse is a common colon cancer model.
Current cancer detection often relies upon anatomical imaging techniques, such as the conventional endoscopy, computed tomography (CT), and ultrasound, followed by a histopathological examination of a biopsied specimen taken from the patient. This conventional method of cancer diagnosis often occurs years after the onset and early stages of the cancer and, therefore, delays early treatment.
Raman spectroscopy has a potential to detect the molecular changes of tissue caused by cancer and, therefore, to allow the detection of cancerous or precancerous lesions at a much earlier stage. Combined with a fiber-optic probe, Raman spectroscopy has the potential to become a new tool for noninvasive, on-line optical biopsies.
Raman Imaging Microscopy for Drug Discovery and Development
Raman imaging microscopy is being developed at SwRI to provide a label-free, nondestructive, and noncontact imaging tool to monitor drug uptake and subcellular distribution in live cells. Knowledge of drug uptake and subcellular distribution or intracellular pharmacokinetics can provide an early indication of drug activity as well as insight into mechanisms of drug resistance and sensitivity before costly preclinical animal and clinical efficacy and toxicity testing is performed.
Raman imaging microscopy can also be used to develop in-vitro assays to determine the absorption, distribution, metabolism, and excretion (ADME) properties of a candidate drug. Thus, Raman imaging technology has the potential to impact several important areas in drug discovery and development.
Raman imaging illustrates the distribution of anticancer drug paclitaxel in a live breast tumor cell. (a) White-light images of an MDA-435 breast tumor cell treated with the drug 4.5 hours ago. (b) Corresponding Raman image of the cell showing only the paclitaxel molecule. (c) Overlay of (a) and (b) showing the drug distribution within the cell. The red arrows point to the cell nucleus region. The blue arrow points to the cell blebbing region, which may indicate the apoptosis of the cell after drug treatment. The color bar indicates the relative Raman signal intensity that increases from bottom to top.
References for Raman Spectroscopy
Ling J., M.A., Cruz E., Weitman S.D., "Cellular Level Drug Mechanism Study Using Raman Imaging," 6th Annual Conference & Exhibition on Drug Discovery Technology, Stuttgart, Germany, April 2002.
Ling J., Weitman S.D., Miller M.A., Moore R.V., Bovik A.C., "Direct Raman imaging techniques for studying the subcellular distribution of a drug," Applied Optics, Vol. 41, No. 28, October 1, 2002.
Related Terminology
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