Direct measurement of the melting temperature of supported DNA by electrochemical method.
The development of biosensors based on DNA hybridization requires a more precise knowledge of the thermodynamics of the hybridization at a solid interface. In particular, the selectivity of hybridization can be affected by a lot of parameters such as the single-strand (ss)DNA density, the pH, the ionic strength or the temperature. The melting temperature, T(m), is in part a function of the ionic strength and of the temperature and therefore provides a useful variable in the control of the selectivity and sensitivity of a DNA chip. The electrochemical technique has been used to determine the T(m) values when the probe is tethered by a DNA self-assembled monolayer (SAM). We have built a special thin layer cell, which allows the recording of the cyclic voltammogram under controlled temperature conditions. T(m) has been determined by recording the thermogram (current versus temperature) of a redox indicator on a double-stranded hybrid (dsDNA) modified electrode and comparison with the corresponding ssDNA response. T(m) of supported DNA varies linearly with the ionic strength. The stability of the SAMs has been considered and comparison between T(m) in solution and on a solid support has been discussed.
Meunier-Prest
Rita
R
Laboratoire de Synthèse et d'Electrosynthèse Organométalliques, UMR CNRS 5188, Université de Bourgogne, 6 Bd. Gabriel, 21000 Dijon, France. rita.meunier-prest@u-bourgogne.fr
Raveau
Suzanne
S
Finot
Eric
E
Legay
Guillaume
G
Cherkaoui-Malki
Mustapha
M
Latruffe
Norbert
N
D004247:DNA / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D004563:Electrochemistry / Q000379:methods*; D004566:Electrodes; D009691:Nucleic Acid Denaturation; D020411:Oligonucleotide Array Sequence Analysis; D009994:Osmolar Concentration; D010084:Oxidation-Reduction; D012680:Sensitivity and Specificity; D013696:Temperature; D013816:Thermodynamics
D004247:DNA