Design of an optical fiber sensor for detecting in situ the composition of pharmaceuticals in blood

This paper reports authors' works on design of an optical fiber sensor which can in situ monitor and analyze the concentration and composition of pharmaceutical in blood. An optical probe is inserted in blood vessels, ultraviolet light is coupled into one branch of Y-type optical fiber to induce fluorescence emitting from the pharmaceutical in blood. The fluorescence is collected by another branch of Y optical fiber and detected by photomultiplier. The detected signal is sampled into computer which can process the data in realtime and display dynamically the fluorescence spectrum on the screen. Compared with ordinary analytical instruments such as various spectrometer and chromatographs, this sensor has the advantages that it can measure in situ and thus omit the process of extracting serum or plasma from blood and reduce the detecting time. This advantage has practical value in clinical diagnosis. In this research, the major difficulty is that the blood is not transparent. Authors apply a membrane adhered to the top of the probe and frustrating the access of hemocytes thus the fluorescence can be collected. This sensor can measure the concentration of pharmaceutical in blood in the grade of micrograms/milliliter.