End-labeling of peptide nucleic acid with osmium complex. Voltammetry at carbon and mercury electrodes

Autoři: Palecek, E., Trefulka, M., Fojta, M.
Rok: 2009


Peptide nucleic acid (PNA), the DNA mimic with electrically neutral pseudopeptide backbone, is intensively used in biotechnologies and particularly in single-base mismatch detection in DNA hybridization sensors. We propose a simple method of covalent end-labeling of PNA with osmium tetroxide, 2,2'-bipyridine (Os,bipy). Os,bipy-modified PNA (PNA-Os,bipy) produces voltammetric stripping peaks at carbon and mercury electrodes. Peak potential (E-p) of one of the anodic peaks of PNA-Os,bipy at the pyrolytic graphite electrode (PGE) differs from E-p of the reagent, allowing PNA-Os,bipy analysis directly in the reaction mixture. At the hanging mercury drop electrode (HMDE) the PNA-Os,bipy yields a catalytic peak Cat(p) in addition to the redox couples. Using Cat(p) it is possible to detect purified PNA-Os,bipy down to 1 pM concentration at accumulation time 60 s. To our knowledge this is the highest sensitivity of the electrochemical detection of PNA. (C) 2008 Elsevier B.V. All rights reserved.