RNA Aptamer-Based CSPs and the Mirror-Image Strategy

3 RNA Aptamer-Based CSPs and the Mirror-Image Strategy 

So L-oligonucleotides are expected to be unsusceptible to naturally occurring enzymes. This concept has been applied successfully to create a biostable RNA CSP. It was demonstrated that a chiral stationary phase based on l-RNA (i.e., the mirror image of the natural d-RNA aptamer) was stable for an extended period of time (about 1600 column volumes of mobile phase) under the usual chromatographic conditions of storage and experiments. In addition, as expected 

Subsequently, an immobilized anti-D-histidine l-RNA aptamer microcolumn has been described, and the retention and enantioselective properties of the CSP have been evaluated (Ruta et al., 2007a). The minimal sequence of the 40-mer RNA aptamer used was obtained via a SELEX procedure directed against L-histidine. This oligonucleotide was known to discriminate strongly between l-and D-histidine (Kd 10 fiM for the L-histidine/aptamer association and about 

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