Use of polymer coated AgClBr fibers for fiberoptic evanescent wave spectroscopy (FEWS) of biological fluids

Silver halide IR-transmitting fibers were coated with polymer films in order to protect them from deterioration caused by interaction with biological fluids. Such coated fibers can be used for human blood serum analysis carried out by Fiberoptic Evanescent Wave Spectroscopy (FEWS) using a Fourier Transform infrared (FTIR) spectrometer. A dip-coating procedure was worked out for coating fibers with polystyrene or silicone-elastomer thin films. Deterioration tests of coated fibers in saline solution that imitates human blood serum salts were performed. These demonstrated that the polymer layers provide protection to the fibers, while making it possible to carry out FEWS measurements.