Chalcogenide glass fibers used for in situ infrared spectroscopy in biology and medicine

Chalcogenide glass optical fibers possess very low optical losses in the middle infrared range from 2 to 12 mm. They were used to implement remote infrared spectroscopy, known as Fiber Evanescent Wave Spectroscopy (FEWS). Due to their hydrophobic behavior, such sensor is especially suitable for application in biology and medicine where water is a nuisance to detect relevant information. Moreover, the design of the sensor using tapered fibers enables to improve the signal to noise ratio. Then, once coupled with unsupervised analysis technique such as Principle Component Analysis (PCA), it has been shown that this tool is efficient to differentiate between obese and control mice by recording their serum FEWS spectra. The same method has been carried out to detect in situ the both phenotypes of a bacterial culture.