INPHAZE researchers have shown that the system can distinguish between single-stranded and double-stranded DNA.
The INPHAZE system is ideal for studying DNA films on solid substrates (such as silicon). DNA base pair interactions can be studied in great detail because the system returns the detailed substructure of the resultant assemblies. It is then possible to look at the binding as a function of pH etc., or the effect of adding a small linker moiety etc. The high resolution EIS that INPHAZE offers can “see” these additional layers or changes in the structure or properties of the films. Similarly, DNA can be studied and, for example, the hybridization of single stranded DNA with its complimentary strand can be seen.
Typically the DNA strands are anchored to a conducting material such as silicon, gold, or glassy carbon. It does not matter if there is a thin oxide layer at the surface as the INPHAZE instrument will resolve that and present that as a layer in its own right. For example silicon wafers oxidize and a thin layer (~2 nm) of insulating silica (SiO2 glass) forms on the surface. In some ways this is an advantage as it provides a built-in control layer for analyzing the structure on top!.
DNA on glassy carbon electrode can be monitored to follow the hybridization of single stranded DNA with its complimentary strand. A single base pair mismatch can be detected in this way. Typically the measurements and analysis can be done in one day!
Citation
Electrical characterizations of biomimetic molecular layers on gold and silicon substrates. T.C. Chilcott, E.L.S. Wong, T. Böcking and H.G.L. Coster. Physiological Measurement, 29, S307–S319, 2008. doi:10.1088/0967-3334/29/6/S26
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