DISSERTATION

_____________________________________________________________ Results and Discussion
3.5 Intercalation as a DNA detection technique
Synthesis of the intercalator was done by Dr. Adrian Ruff. Results from this chapter are
included in the manuscript to be submitted: “Amperometric detection of dsDNA via acrydinium
orange modified glucose oxidase” with coauthors: D. Jambrec, A. Ruff, W. Schuhmann, written
by A. Ruff (synthesis part) and the author.
In order to implement electrochemical sensing platforms into point-of-care diagnostic devices
plenty of improvement still needs to be done. Besides the design of the sensing platform, the
applied strategy for the sensing process itself is of tremendous importance defining the
sensitivity of the chosen approach. Even though covalent labelling of target DNA using dyes
or enzymes significantly enhances the sensitivity of DNA detection schemes, it demands
sample preparation and lacks of simplicity 101 . In contrast, label-free electrochemical detection
methods provide several advantages such as miniaturization, fabrication of low cost devices,
operation simplicity and rapid detection time. Therefore, they are of particular interest in
personal diagnostics using point-of-care devices 102 .
Among label-free approaches, sandwich-type assays, in which a third labelled signaling
sequence hybridizes the overhang of the target DNA sequence, have been extensively
investigated. Nevertheless, this strategy requires the use of different sequences for each
investigated target DNA, which increases the complexity and cost of the assay. Furthermore,
3.5 Intercalation as a DNA detection technique 96