Humidity effects on the conductance of the assembly of DNA molecules

We have studied the effects of relative humidity on the conductance of the assembly of poly(dG)–poly(dC) and poly(dA)–poly(dT) DNA molecules. The exponential dependence of conductance on the relative humidity is observed and explained in terms of ionic conduction through the hydration layers around DNA. The poly(dG)–poly(dC) specimen has larger sensitivity to the relative humidity and smaller activation energy for the ionic conduction than the poly(dA)–poly(dT) specimen. Our results show that the conductance of a specimen consisting of multiple DNA molecules might be strongly affected by the relative humidity.