An　electrogenerated　chemiluminescence　(ECL)-DNA　sensor　was　designed　and　fabricated　for　the　investigation　of　DNA　damage　by　a　potential　environmental　pollutant,　perfluorooctanoic　acid　(PFOA).　The　ECL-DNA　sensor　consisted　of　a　Au　electrode　that　had　a　self-assembled　monolayer　of　15　base-pair　double-stranded　(ds)　DNA　oligonucleotides　with　covalently　attached　semiconductor　CdSe　quantum　dots　(QDs)　at　the　distal　end　of　the　DNA.　Characterization　of　the　ECL-DNA　sensor　was　conducted　with　X-ray　photoelectron　spectroscopy　(XPS),　electrochemical　impedance　spectroscopy　(EIS),　ECL,　and　cyclic　voltammetry　before　and　after　the　exposure　of　the　sensor　to　PFOA.　Consistent　data　revealed　that　the　dsDNA　on　Au　was　severely　damaged　upon　the　incubation　of　the　electrode　in　PFOA,　causing　significant　increase　in　charge　(or　electron)　transfer　(CT)　resistance　within　DNA　strands.　Consequently,　the　cathodic　coreactant　ECL　responses　of　the　Au/dsDNA-QDs　electrode　in　the　presence　of　K2S2O8　were　markedly　decreased.　The　strong　interaction　between　DNA　and　PFOA　via　the　hydrophobic　interaction,　especially　the　formation　of　F　center　dot　center　dot　center　dot　H　hydrogen　bonds　by　insertion　of　the　difluoro-methylene　group　of　PFOA　into　the　DNA　base　pairs,　was　believed　to　be　responsible　for　the　dissociation　or　loosening　of　dsDNA　structure,　which　inhibited　the　CT　through　DNA.　A　linear　relationship　between　the　ECL　signal　of　the　sensor　and　the　logarithmical　concentration　of　PFOA　displayed　a　dynamic　range　of　1.00　x　10(-14)-1.00　x　10(-4)　M,　with　a　limit　of　detection　of　1.00　x　10(-15)　M　at　a　signal-to-noise　ratio　of　3.