Laser-based optical fiber fluoroprobes in clinical analysis

Optical fiber fluoroprobes have been designed to perform molecular fluorescence measurements in minute volumes of body fluids. The fluoroprobes are evaluated for conventional laser excited, two-photon excited, and sequentially excited modes of fluorescence detection. In-vitro investigations of test compounds in various biological matrices, including cerebral spinal fluid and whole blood, revealed comparable limits of detection (approximately 5 x 10^-7 M) for the three fluorescence techniques. Linear dynamic ranges are shown to be solvent dependent and superior for the non-linear excited fluorescence techniques. The results of in-vivo measurements of the anti-tumor drug Adriamycin in tumor bearing laboratory mice are also reported. The capacity of various fluoroprobe designs to provide Adriamycin concentration measurements in tumor interstitial fluid is clearly established. In addition, independent analytical confirmation of these in-vivo measurements is provided by conventional in-vitro techniques. The ultimate detectibility and selectivity of fluoroprobe utilization is also discussed.