Resistive-pulse Sensing of DNA with a Polymeric Nanopore Sensor and Characterization of DNA Translocation

Abstract

The ability to detect DNA strands and determine their characteristics in solution plays a critical role to design a sensor in terms of its biophysical properties and receives attention in whole- genome sequencing. In this study, we report a simple method to detect 100-bp DNA based on resistive-pulse sensing and its characteristics in terms of analyte concentration, potential, tip size. and electrolyte concentration. Track-etched polyethyleneterephtalate (PET) nanopores were used and modified (w/EDC-NHS coupling) to decrease the negative surface charge and promote DNA translocation. We tuned up the tip diameters of nanopores by using symmetric and asymmetric chemical etching. The tip diameters ranged from 21 nm to 42 nm. To show the electrophoretic nature of translocation, we investigated the concentration and potential dependence. The current-pulse events were observed down to 600 mV (4 +/- 1 events/min) and 0.25 nM was the minimum concentration. Both potential and concentration dependence showed linear behavior which agreed to previous studies. The effect of tip size was also studied and its effect on translocation frequency was discussed. Finally, the change in current-pulse amplitude and duration as a function of electrolyte concentration was studied and longer duration values (14.3 +/- 1.4 ms) were observed. Our findings provide a guide to translocate the charged molecules more efficiently and help to understand the translocation dynamics of short DNA molecules in resistive-pulse sensing.