Molecular target-ligand selectivity

SELEX (systematic evolution of ligands by exponential enrichment) is used to generate aptamers, oligonucleotides selected to tightly bind a specific molecular target. The process is generally automated to allow rapid identification of one or more aptamers with the desired binding specificity. 

At this time, low-molecular weight ligands of high denticity with a large number of different donor groups represent chemical curiosities rather than a target of concerted study, since their complexities in terms of potential isomers, variable coordination modes, and metal ion selection appear to outweigh any short-term potential usefulness. 

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