Abstract
We measured the electrical characteristics of DNA molecular bundles that were 25-µm long and had a diameter of 100-500 nm. We captured the bundle between the tips of silicon nanotweezers by dielectrophoresis. The two-terminal measurement, which used only the tweezers, failed because of the contact resistance between the bundle and the tips. We adopted a four-terminal measurement that eliminated the effect of the contact resistance. We fabricated potential measurement probes, which consisted of 2-µm-wide line electrodes with a 4-µm separation. The captured DNA bundle was pressed against the probes, and the potential drop associated with the current in the bundle was measured. We successfully determined the conductivity of the bundle.
