Electrostatic Cycling of Hybridization Using Nonionic DNA Mimics

This study demonstrates efficient electrostatic control of surface hybridization through use of morpholinos, a charge-neutral DNA mimic, as the immobilized “probes”. In addition to being compatible with low ionic strengths, use of uncharged probes renders the field interaction specific to the nucleic acid analyte. In contrast to DNA probes, morpholino probes enable facile cycling between hybridized and dehybridized states within minutes. Impact of ionic strength and temperature on the effectiveness of electrostatics to direct progress of hybridization is evaluated. Optimal electrostatic control is found when stability of probe–analyte duplexes is set so that electrostatics can efficiently switch between the forward (hybridization) and reverse (dehybridization) directions.