Discovery of two–dimensional condensation of nucleic acids components at the mercury electrodes – 45 years’ history

Purine and pyrimidine derivatives currently occurring in nucleicacids posses an extraordinary high ability of self–association at theelectrode surface and can form there by a two–dimensional (2D)condensation a compact self-assembled monolayer. By this highcondensation ability nucleic acid bases differ from most of the otherpurine and pyrimidine derivatives which currently do not occur innucleic acids. A regular arrangement of nucleic acid bases,nucleosides and nucleotides leading to 2D condensation takes placenot only at the liquid mercury surface, but also on the mercury filmmodified carbon/graphite, solid amalgam, or atomically flat singlecrystalmetal electrodes. With polymeric DNA and/orpolynucleotides this kind of 2D condensation has not been observed.Recently, we have shown that synthetic homo- and heteropyrimidinicoligodeoxynucleotides (ODNs) can 2D condensate atthe negatively charged mercury and solid amalgam surfaces.Formation of the ODN condensed film took place even in theabsence of any ODN in the bulk solution (ex situ 2D condensation).No such 2D condensed monolayer was observed with homo- andhetero-purinic ODNs giving only tensammetric(desorption/reorientation) peaks in weakly alkaline pHs within thesame potential region.