PNA Chips

Definition Peptide nucleic acid (PNA) is an artificial mimic of nucleic acid, which was invented more than a decade ago (7). The molecule combines many features that are similar to those of natural nucleic acids with characteristics that are rather different or even unique to PNA. First and foremost, N-(2-aminoethyl)-glycine units linked by ▶amide bonds substitute the (deoxy)ribosephosphate backbone and the nucleobases are attached via a methylene carbonyl link to the glycine moiety. Nevertheless, the distances and angles within PNA oligomers much resemble the conformation of nucleic acids (Fig. 1). One format of application is the microarrays that are made for a highly parallel analysis of nucleic acids. To this end, very many different PNA molecules are attached onto a small planar surface, e.g. a microscope slide. Upon addition of a DNA or RNA sample, hybridisation occurs on the chip at PNAoligomers that are of complementary sequence to molecules in the sample. Recorded by detecting a label that is attached to the DNA or RNA, various forms of information can be deduced from such studies, such as for example, sequence variations or changes in the amount of an individual RNA molecule within a complex mixture.