posted on 2015-04-07, 00:00authored byTadao Takada, Mai Takemura, Yuta Kawano, Mitsunobu Nakamura, Kazushige Yamana
We
describe a simple and convenient method for the preparation
of photoresponsive DNA-modified electrodes using primer extension
(PEX) reactions. A naphthalimide derivative was used as the photosensitizer
that was attached to the C5-position of 2′-deoxyuridine-5′-triphosphate
(dUTPNI). It has been found that dUTPNI is a
good substrate for the PEX reactions using KOD Dash and Vent (exo-)
enzymes in solutions to incorporate naphthalimide (NI) moieties into
the DNA sequences. On the electrode surface immobilized with the primer/template
DNA, the PEX reactions to incorporate dUTPNI molecules
into the DNA sequence were found to efficiently proceed. With this
solid-phase method, the DNA monolayers capable of generating photocurrent
due to the photoresponsive NI molecule can be constructed. It was
shown that the photocurrent generation was significantly suppressed
by a single-nucleotide mismatch included in the primer/template DNA,
which is applicable for the design of photoelectrochemical sensors
to discriminate single-nucleotide sequences.