Optical Fiber Fluoroprobes for Biological Measurements

Abstract

An optical fiber fluoroprobe has been designed to make in vivo fluorescence measurements in minute volumes of body fluids. The fluoroprobe is evaluated for conventional laser excited, two-photon excited, and sequentially excited modes of fluorescence detection. Limits of detection, approximately 5 × 10−7 M, were determined for test compounds measured in various solvents including cerebral spinal fluid and whole blood, and are comparable for the three fluorescence techniques. Linear dynamic ranges are shown to be solvent dependent and superior for the nonlinear excited fluorescence techniques. The ultimate detectability and selectivity of this technique are also discussed.