Conjugation of (E)-5-[2-(Methoxycarbonyl)ethenyl]cytidine to Hydrophille Microspheres: Development of a Mobile Microscale UV Light Actinometer

(E)-5-[2-(Methoxycarbonyl)ethenyl]cytidine was biotinylated through a diisopropylsilylacetal linkage and attached to the surface of hydrophilic streptavidin-coated microspheres through the high-affinity noncovalent interaction between biotin and streptavidin. The functionalized microspheres form a stable suspension in water. Upon UV irradiation, the nonfluorescent (E)-5-[2-(methoxycarbonyl)ethenyl]cytidine on the microspheres undergoes photocyclization to produce highly fluorescent 3-β-D-ribofuranosyl-2,7-dioxopyrido[2,3-d]pyrimidine. The fluorescence intensity of the microspheres can be correlated to the particle-specific UV doses applied at different suspension concentrations. The microspheres allow one to measure the UV dose (fluence) distribution in high-throughput water disinfection systems. [PUBLICATION ABSTRACT]