Advanced infrared glasses for biochemical sensing

This chapter reviews the use of fiber evanescent wave spectroscopy (FEWS) for the characterization of biological materials. It focuses on the use of chalcogenide fibers and their application in biochemical sensing. The FEWS technique is a recent but promising analytical method for the study of biointerfaces. It makes use of infrared transparent fiber probes to guide the light source to the sample and collect the resulting signal onto a detector. This technique has recently gained much interest and has found applications in a wide range of fields, including biomedical sensing, cancer diagnosis, and in vivo monitoring of cells. It combines the advantages of Fourier transform infrared (FTIR) with the versatility of fiber sensing. This provides high selectivity of FTIR as well as the ability to probe biointerfaces in situ and in real time. Moreover, the design of appropriate sensing probes can lead to a notable increase in sensitivity and the hydrophobic nature of the glass surface promotes the signal of biomolecule versus water, making this technique a great candidate for biosensing in aqueous environments. The field of FTIR is in constant development and new improvements are regularly reported. In most cases these new advances can be directly applied to the FEWS technique and should further increase its sensitivity and detection limit in the future.