DNA bases make artificial ion channels
doi:10.1038/nindia.2015.22 Published online 18 February 2015
Researchers have synthesized artificial ion channels through the self-assembly of DNA bases attached with sugars1. These channels successfully transported ions when embedded in artificial bilayers that mimic natural cell membranes. They are potentially useful for replicating the functions of natural ion channels — targets for developing antibacterial drugs and drug-delivery systems.
Natural ion channels transport ions essential for proper functioning of living cells. The researchers attached guanosine (guanine attached to a sugar) with cytidine (cytosine attached to a sugar) through a catalyzed chemical reaction known as cycloaddition. The guanosine and cytidine then self-assembled through the formation of hydrogen bonds, giving rise to the synthetic ion channels.
The researchers performed electrochemical measurements by embedding the ion channels in artificial bilayers that are similar to cell membranes. By preparing solutions that mimic physiological conditions, they probed the ability of the channel to conduct current and transport potassium ions.
Like natural ion channels, the synthetic ones exhibited two distinct conductance levels for transporting potassium ions: one near 0.64 nanosiemens and the other near 2.9 nanosiemens. In contrast, no measurable conductance was found in experiments performed without the synthetic ion channels.
In addition, the researchers found that the activity of the synthetic ion channels was inhibited by the DNA base cytosine. “This type of inhibiting is highly important for potential drug-delivery systems that can control the flow of ions or drugs through the cell membrane,” says lead researcher Jyotirmayee Dash.
[The authors of this work are from: Department of Organic Chemistry, Indian Association for the Cultivation of Science, Kolkata and Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, India, and Institute of Organic and Biomolecular Chemistry, Georg-August University Gottingen, Gottingen, Germany.]
1. Das, R. N. et al. A DNA-inspired synthetic ion channel based on G−C base pairing. J. Am. Chem. Soc. 137, 34–37 (2015)