Revolutionizing Animal Care With Raman Spectroscopy

By John Oncea, Editor

Raman spectroscopy offers rapid, non-invasive disease detection in animals. It analyzes molecular vibrations in samples, aiding cancer diagnosis and treatment monitoring in veterinary medicine.

The pinna in the right ear of my cat Chloe was swollen to the point where it looked like she had a fur-covered golf ball on her head. The vet determined it was a hematoma and prescribed Meloxicam and the application of a warm compress to her ear twice a day to help break up the blood that was pooling there.

Fortunately, this was a minor problem diagnosed with little more than a physical exam. But for more serious veterinary problems, Raman spectroscopy is emerging as a powerful tool, offering non-invasive and rapid methods for disease detection and treatment monitoring in animals.

A Brief Look At The Evolution Of Spectroscopy

Spectroscopy can trace its origins back to Isaac Newton who, in the late 1600s, demonstrated through his experiments with prisms how white light can be split into a spectrum of colors. “Similar to many scientific concepts, spectroscopy developed as a result of the cumulative work of many scientists over many decades,” writes Pasco.

Newton’s optics experiments were built on foundations created by Athanasius Kirche, Jan Marek Marci, Robert Boyle, and Francesco Maria Grimaldi. Others built on Newton’s work, from William Hyde Wollaston’s creation of the first spectrometer in 1802 to Neils Bohr’s formulation of his quantum mechanical model of the atom in 1913.

Then, in 1928, Sir Chandrasekhara Venkata Raman first observed the Raman effect, earning the Nobel Prize in Physics in 1930 for his efforts. The 1970s saw the development of the first Raman microscopes, allowing for the probing of minute sample quantities and opening the door for imaging in Raman spectroscopy.

Holographic gratings were introduced commercially around 1972, bringing with them a drastic reduction in stray light levels and the elimination of ghosts, improving the quality of Raman spectra. Charge coupled devices (CCDs were developed in the late 1970s and early 1980s, providing improved sensitivity for Raman detection and significantly faster spectral acquisition1.

To take full advantage of CCD technology, companies like Spex, Jobin-Yvon, and Dilor redesigned spectrometers to achieve a flat field image over a larger width while correcting for optical aberrations during the 1980s, notes HORIBA.

The Jobin Yvon T64000 triple-stage Raman spectrometer was introduced in 1988 and the LabRAM concept was launched five years later, introducing the first true confocal single-stage Raman Microscope.

More recently, MNDP writes that surface-enhanced Raman spectroscopy has greatly enhanced the sensitivity of Raman spectroscopy, allowing for the detection of single molecules. In addition, the development of fiber optic Raman probes has enabled in-situ and remote sensing applications.

What Is Raman Spectroscopy?

Raman spectroscopy is a non-destructive chemical analysis technique that provides detailed information about materials' chemical structure and composition. It is based on the interaction of light with the chemical bonds within a material and relies on the inelastic scattering of photons, known as Raman scattering.

When monochromatic light (usually from a laser) interacts with a sample, most of the light is scattered elastically (Rayleigh scattering) at the same wavelength as the incident light. A small fraction (about 1 in 10 million photons) is scattered inelastically at different wavelengths (Raman scattering).

The sample is illuminated with a laser beam in the visible, near-infrared, or near-ultraviolet range. The laser light interacts with molecular vibrations, phonons, or other excitations in the system. This interaction results in the energy of the laser photons being shifted up or down and the energy shift provides information about the vibrational modes in the system.

Raman spectroscopy can reveal chemical structure, phase and polymorphism, crystallinity, and molecular interactions. During spectrum analysis, a Raman spectrum shows the intensity and wavelength position of the scattered light. Each peak in the spectrum corresponds to a specific molecular bond vibration and the spectrum serves as a distinct chemical fingerprint for a particular molecule or material.

Raman spectroscopy is non-destructive, requires little to no sample preparation, can be used to analyze samples through transparent containers, provides rapid results, and can be used for qualitative and quantitative analysis. It can be applied to solids, liquids, and gases, and is used in chemistry, materials science, pharmaceuticals, biology, and art and archaeology. It also can be used in veterinary medicine.

Uses Of Raman Spectroscopy In Veterinary Medicine

Raman spectroscopy has shown promising results in veterinary medicine, including in the detection of cancer in dogs through urine analysis. According to The National Center for Biotechnology Information, this technique can rapidly (within 15 seconds) distinguish molecular vibrations in urine samples, create a multimolecular spectral fingerprint related to the chemical composition of urine, and detect the broad presence of cancer as well as specific types like lymphoma, urothelial carcinoma, osteosarcoma, and mast cell tumors. This non-invasive method could significantly improve cancer detection and management in dogs, especially for breeds predisposed to certain types of cancer.

Raman spectroscopy also has been applied to analyze animal diets and identify species. A handheld Raman spectroscopy device was evaluated for differentiating animal species and estimating diet characteristics through fecal analysis, a method that can provide insights into an animal’s nutritional status and help optimize feeding strategies.

The application of Raman spectroscopy extends beyond cancer detection and feeding strategies – it can be used to distinguish between healthy and sick animals across various species. According to Nature, this technique shows promise for multiple animal disease testing cases. In addition, Raman spectroscopy is being explored for detecting and managing diseases of the central nervous system in animals.

Among the reasons veterinary medicine is turning to Raman spectroscopy is the fact it's non-invasive with many applications involving analyzing easily obtainable samples like urine or feces. In addition, results can be obtained quickly, often within seconds. Finally, Raman spectroscopy is versatile and sensitive, allowing it to be applied to various species and diseases and detect subtle changes in molecular composition related to disease states.

By providing quick, accurate, and non-invasive diagnostic capabilities, Raman spectroscopy is poised to become an invaluable tool in veterinary medicine. Its ability to detect diseases early and monitor treatment progress could significantly improve animal health outcomes and guide more effective treatment strategies.