Analytical nucleic acids as universal tool for the sensitive detection of bio molecules

Daniela M. Köster

The project aims to establish a new sensitive detection method for microarrays based on the principle of rolling circle amplification (RCA). DNA Microarrays are mainly used to analyse the occurrence of genes and the frequency of transcripts. For common DNA and RNA microarray analyses the samples are amplified in advance.
In contrast to an error prone amplification of the analyte we amplify the readout signal itself via rolling circle amplification. The advantage of the RCA is an isothermal DNA amplification of a circular DNA template. The amplification results in a single stranded rolling circle product (RCP) with thousands of tandemly linked copies connected to the analyte molecule. The product can be detected directly using labelled nucleotides (fluorescence, enzyme) or DNAzymes. These so called DNAzymes are DNA molecules with a catalytic activity, thereby labelling of the amplicon renders unnecessary due to the enzymatic activity of the amplified product. The used DNAzyme in this approach has a peroxidase like activity. The advantage is the possibility to directly detect DNA on microarrays or in liquid assays just by the conformation of the sequence. This promising project will provide a RCA based detection method on microarray platforms, which consumes only reduced amounts of sample without compromising sensitivity.

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