The power of the Mid Infrared spectroscopy
MIR: Capturing the fundamental vibrations of biological molecules
The mid infrared wavelengths (between 2 and 20 µm) include fundamental vibration signatures of major molecules that compose the tissues and biological fluids.
Therefore, the absorption spectrum in mid-infrared of a biologic element is representative of its composition because it accurately reflects the structure of the molecules constituting the sample, providing a comprehensive metabolic profile.
One can quickly see the interest of such technique: instead of focusing on several biomarker because they are measurable, this technique detects the results of all markers in the sample, even the one we can’t identify or measure individually for now. This is more extensive and faster than metabolomics.
It is then possible to classify the spectrum of measured sample relatively to healthy cases and pathological cases references. This classification gives a score to help diagnosis.
Infrared spectroscopic analysis thus allows to obtain a score for a diagnosis from observation of all molecular characteristics of the sample (There is a very large number of distinct biomolecules present) and not based on the analysis of a small number of identified markers a priori.
A proven technology
The principle of spectroscopy (1st work in the fourteenth century) at large (gamma rays, X-rays, visible and ultraviolet, Infrared, Microwave, Radio Frequency) is used by a multitude of specialized experimental techniques. It is applied in almost all the fields of physics: astronomy, biophysics, chemistry, physics, atomic, plasma physics, nuclear physics, solid state physics, mechanics, acoustics ….
Infrared spectroscopy is a compelling technology for analytical chemistry, which two objectives are to identify and quantify some type of molecule in a complex sample.
It is widely used in academic research or industry as simple and safe technique of measurement, quality control and dynamic measurement.
Its use in the biological diagnosis has been restricted due to sampling methods.
- Measurement by transmission by placing a sample between two infrared transmitting plates, is sensitive but complicated to implement.
- By direct reflection or ATR plate; Implementation is simpler as sample has just to be deposited on the measurement area, but the sensitivity is limited.