Investigation of DNA induced autocatalytic copper deposition
Gyula Jágerszki
Department of Inorganic and Analytical Chemistry
Budapest University of Technology and Economics
H–1111 Budapest
Advisors: Klára Tóth
Róbert E. Gyurcsányi
The sensitive analysis of specific DNA strands involves in most cases
labeled probes. To avoid the use of these expensive secondary reagents while still
ensuring the high sensitivity of the DNA assay we have been interested to explore
the possibility of DNA induced autocatalytic metal deposition. The metallization of
DNA strands for the fabrication of metallic nanowires has been already reported,
however, the analytical application of the metal deposition is still unexplored. The
analytical use of DNA induced metal deposition requires a selective deposition
process with considerable amount of metal growth on DNA modified surface.
In this work we have investigated the electroless deposition of copper on
DNA modified gold surfaces. The autocatalytic copper deposition was studied on
gold surfaces modified with different thiols bearing various chemical functionalities
to identify functional groups enhancing or resisting to copper deposition.
In the same time a careful optimization of the electroless deposition
conditions, were performed and adapted for the analytical application. Variation of
the oxygen content of the deposition solution was identified as major factor
influencing reproducibility of the copper growth on different surfaces and therefore
a flow through system was developed in which deaerated deposition could be used.
When using backgrounds resisting to the copper deposition, such as
mercaptohexanol, we have succeeded to visualize the surface bound DNA strands.
Moreover, the methodology developed could differentiate between the different
base length DNA sequences. The amount of copper deposited was determined by
anodic stripping voltammetry based on calculating the electrical charge involved in
the oxidative dissolution process. The method proposed for DNA detection might be
useful for peptide nucleic acid and aptamer based assays.
-10
8x10
-10
7x10
-10
6x10
nCu, mol
-10
5x10
-10
4x10
-10
3x10
-10
2x10
-10
1x10
0
DNA27
DNA81
DNS13
MH
MH
The amount of copper deposited on gold surfaces modified with 27, 81 and 13 base
length DNAs (DNA27, DNA81, DNA13) and mercaptohexanol (MH)
[1]
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