A HOMOGENEOUS AFFINITY FLUORESCENCE ASSAY SYSTEM FOR GALACTOSE MONITORING

Since the systemic venous-hepatic venous galactose gradient is normall y quite large, the ability to detect different blood galactose concent rations in vivo would provide a mechanism for anatomic localization of the hepatic venous system, Furthermore, the development of a catheter assembly mounted with a galactose-sensitive biosensor would provide a technique for cannulating this organ system entirely using sensor gui dance. In this report we describe a homogeneous affinity fluorescence assay system which can be contained in a dialysis hollow fiber for con tinuous galactose monitoring. The principle of this assay is based upo n competition of freely permeable galactose for the specific binding i nteractions between a fluorescently labeled polysaccharide and lectin reagent pair, This competetive energy-transfer assay exhibits good sen sitivity over a physiologically relevant galactose concentration range (0-2 mM), an acceptable response time (< 200 s) and small dimensions, which make it potentially adaptable to conventional catheter systems for in vivo use. Such a system would greatly simplify diagnostic effor ts to evaluate hepatic function in real time.