Temperature effect on translocation speed and capture rate of nanopore-based DNA detection

Abstract

We study the effects of electrolyte temperature on DNA molecule translocation experimentally without and with a temperature gradient across nanopore membranes. The same temperatures on both electrolyte chambers are first considered. The DNA molecule translocation time is measured to be 2.44 ms at 2°C in both chambers, which is 1.57 times longer than at 20°C. Then the temperature difference effect is characterized in both chambers. The results show that the DNA translocation speed can be slowed down as long as one side temperature is lowered, irrespective of the temperature gradient direction. This indicates that the thermophoretic driving force generated by a temperature gradient has no obvious effect on the threading speed of DNA molecules, while the main reason for the slowed DNA translocation speed is the increased viscosity. Interestingly, the capture rate of DNA molecules is enhanced under a temperature gradient condition, and the capture rate during DNA translocation from hot side at 21°C to cold one at 2°C is 1.7 times larger than that under the condition of both chambers at 20°C. Finally, an optimized configuration is proposed to acquire higher capture rates and lower DNA translocation speeds.