Fiber optic biosensor for detection of DNA damage Original Research Article

This paper describes a fiber optic biosensor for the rapid and sensitive detection of radiation-induced or chemically-induced oxidative DNA damage. The assay is based on the hybridization and temperature-induced dissociation (melting curves) of synthetic oligonucleotides. The hybridization pair consists of a biotin labeled 38 mer oligonucleotide immobilized to a streptavidin-coated optical fiber and a fluorescently-labeled near-complementary (two base mismatch) oligonucleotide reporter sequence. The hybridization-based assay detected 50 nM labeled probe and could be run up to 10 times on the same fiber. Melting profiles were sensitive to high energy radiation and to 3-morpholinosydnonimine (SIN-1)-generated reactive decomposition products. The dynamic range of the assay for ionizing radiation extends from 20 to 1000 cGy. Oxidative damage induced by SIN-1 was measured over a concentration range of 250 μM to 3 mM.