Functional BOD-Ad-Cmyc@BSA complex nanosensor for Cu(II) and the detection of live E. coli.

Abstract Escherichia coli (E. coli) is abundantly present in nature. It is generally harmless to humans but some strains have been deemed very dangerous. Therefore, as an indicator of hygienic testing, the detection of E. coli is essential. In this work, a fluorescent assembly was synthesized and characterized by spectroscopic methods. It was found that the amantadine (Ad) conjugated dye (BOD-Ad) intercalated into Cmyc G4 (aptamer) forming a non-emission assembly (BOD-Ad-Cmyc), which could be lighted-up by BSA due to the formation of fluorescence nanoparticle BOD-Ad-Cmyc@BSA. Further, BOD-Ad-Cmyc@BSA can selectively bind Cu2+ forming non-emission species BOD-Ad-Cmyc@BSA-Cu2+. E. coli can turn-on the emission of BOD-Ad-Cmyc@BSA-Cu2+ system due to the copper accumulation or reduction by E. coli. Therefore, a fluorescence method for the determination of E. coli was built. The detection limit of BOD-Ad-Cmyc@BSA-Cu2+ of E. coli is 6.3 CFU/mL. Thus, this BOD-Ad-Cmyc@BSA-Cu2+ fluorescent assembly can be used for the detection of live E. coli in the environment.