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ICC Water & Health employee receives DOC fellowship from the Austrian Academy of Sciences

Claudia Kolm was awarded a DOC fellowship from the Austrian Academy of Sciences (ÖAW) for her project "Selection and characterization of DNA aptamers for health-relevant bacteria in water". Her project was presented in a poster exhibition from 9th to 14th June 2017 in the auditorium of the ÖAW.


Development of DNA aptamers

The Austrian Academy of Sciences offers each year DOC fellowships to doctoral candidates for the promotion of junior scientists. The awarded project deals with the development of DNA aptamers, which offer great potential as molecular recognition molecules in biosensing applications.

Aptamers are short, single-stranded oligonucleotides (DNA or RNA) with the ability to recognize and bind to a target with high affinity and selectivity by folding into complex three-dimensional structures. These functional nucleic acids are more robust compared to their antibody counterparts (in terms of temperature, pH, shelf-life, etc.) and can be readily produced via chemical synthesis in large quantities and at relative low costs with virtually no batch-to-batch variations. Moreover, aptamers can be modified with chemical groups and fluorescence dyes in a targeted manner.

Unlike antibodies, aptamers are identified by an in vitro selection method termed "SELEX" (Systematic Evolution of Ligands by Exponential Enrichment). In SELEX, aptamers evolve from random oligonucleotide libraries by repetitive binding of oligonucleotides to target molecules, partitioning and subsequent exponential amplification. This process allows to vary the selection conditions and thus to select aptamers that recognize their target molecule under the desired assay conditions (buffer, pH, ionic strength, temperature). A DNA/RNA pool of 1014 – 1016 individual sequences serves as a starting point for the selection.

The aim of the two-and-a-half-year project is to select and characterize genus-specific Enterococcus DNA aptamers (enterococci as a model) that can be used for biosensing purposes, cell imaging and flow cytometry. The project is carried out by Claudia Kolm within the Molecular Diagnostics working group at the IFA-Tulln and in a collaboration with the ICC Water & Health (TU Wien and Medical University of Vienna) and the Carleton University in Ottawa, Canada.