Ferrocenyl naphthalene diimide can bind to DNA-RNA hetero duplex: potential use in an electrochemical detection of mRNA expression

The novel ferrocenyl naphthalene diimide derivative I was synthesized by th e condensation reaction between ferroceneacetic acid and terminal amino moi eties of two imide substituents of naphthalene diimide. Stopped-flow analys is of the ligand I and DNA interaction revealed the following results: (i) the ligand binds to double stranded DNA more strongly than to single strand ed DNA; (ii) the ligand does not have a bias against DNA sequence; (iii) th e ligand can bind to the DNA-RNA hetero duplex more strongly than to the DN A-DNA duplex. These properties of I make it a suitable ligand for analysis of not only DNA but RNA. In fact, a current due to I was observed at 269 mV in the differential pulse voltammetric analysis of dA(20)-immobilized elec trode in an electrolyte containing 1. The current increased markedly upon h ybridization with polyU, whereas no current increase was obtained for polyA . Since the DNA-RNA hetero duplex is formed between sample RNA and DNA on t he electrode, I may be used for the electrochemical detection of mRNA expre ssion. (C) 2001 Elsevier Science B.V. All rights reserved.