Comparison of DNA Hybridization at Rotating and Heated Gold Disk Electrodes

Abstract

This paper reports about the influence of temperature, hybridization time and convection upon the detection of osmium tetroxide bipyridine-labeled target oligonucleotides at rotating gold disk (RDE) and heated low temperature co-fired ceramics (LTCC) gold disk electrodes. We used mixed self-assembled monolayers of hexathiol-linked probe oligonucleotides and mercaptohexanol on the gold surface of the electrodes for the hybridization detection of the labeled targets by means of square-wave voltammetry. Due to protective strands, the osmium tetroxide-modified target strands were still able to hybridize with the immobilized probe strands. The hybridization of such osmium tetroxide bipyridine-modified target strands with thiol-linked probe strands immobilized on gold yielded large reversible square-wave-voltammetric signals. Rotation speed and, hence, mass transport due to convection has only marginal effects. On the other hand, temperature affects greatly the hybridization step as indicated by both heated LTCC electrode in cold and RDE in warm hybridization solution. Calculated detection limits of 3.6 and 3.1 nM targets at the RDE and the LTCC electrode, respectively, have been almost the same at both types of electrodes. Applying an appropriate temperature during hybridization is more important than mechanically enhanced mass transport.

Template‐Free Galvanic Nanostructuring of Gold Electrodes for Sensitive Electrochemical Biosensors

“…Dehybridizing in 50 8C warm water gave a signal of about 5 mA. This indicates good regeneration capability and corresponds with former observations reporting a remaining signal height of about 10% on this type of probemodified gold electrodes after dehybridization [47].…”

“…A 5 mL droplet of [OsO 4 (bipy)]-labeled target solution of a given concentration was placed at the electrode surface to allow for hybridization in a water saturated atmosphere for one hour. The modification and hybridization procedure has been described earlier in full detail [46,47]. Dehybridization was performed by incubation in deionized water at 50 8C for 60 s. The sequence MON 810 (5'-TTTTTGTTGTCC-ATGGCCGCTTGGTATCT-3') was used as a noncomple- …”

“…The accessible active gold surface was determined with a PalmSens potentiostat (Palm Instruments BV, The Netherlands) by cyclovoltammetry (CV) in 0.5 M sulfuric acid [13,47,52]. The 20 mL electrochemical cell comprised an Ag/ AgCl (3 M KCl) reference and a platinum counter electrode (Metrohm).…”

Electrochemical Detection of Asymmetric PCR Products by Labeling with Osmium Tetroxide

“…We recently reported about the application of covalently attached redox markers together with thiol-linked probe oligonucleotides on heated gold electrodes [3].…”

Carbon Nanotube Electrodes for Hot‐Wire Electrochemistry

“…In this case, a thermal stirring effect becomes predominant, which has been used for electroanalysis, namely, in stripping analysis, [4][5][6] determination of volatile components, [7] biosensors, [8] and for DNA hybridization studies. [9][10][11] Electroluminescence has been studied with heated electrodes as well. [12,13] For the in situ heating of electrodes, thin wires with diameter in the micrometer range are advantageous due to their extremely fast heating-up and coolingdown processes.…”