Label-free DNA hybridization based on coupling of a heated carbon paste electrode with magnetic separations

The technique of electrically heated carbon paste electrodes is applied for label-free detection of DNA hybridization after magnetic isolation. Coupling of both techniques leads to highly selective and sensitive detection of DNA hybridization. Minimal contributions of nonhybridized DNA are thus coupled to an enhanced signal. Application of elevated temperatures during the accumulation step yields a max. 6-fold enhancement of guanine oxidation signals compared to room temperature deposition. Use of noncomplementary nucleic acids gives no significant peaks at room or elevated temperatures. The noise level remained unaffected. Variation of the target concentration results in linear calibration plots under hot accumulation conditions.