Enhancing DNA Translocation\nPerformance and Conformational\nChanges in Quartz Nanopipettes by Ionic Liquid Modification

The low signal-to-noise ratio (SNR), short dwell time,\nand complex\nDNA folding conformations remain significant challenges in DNA translocation\nsensors. This study utilized ionic liquid (IL) modification to enhance\nthe DNA translocation performance and conformational changes. Initially,\nthe impact of various types of ILs on ion current behavior and λ-DNA\ntranslocation was investigated. The results indicate that [Bmim][N(CN)<sub>2</sub>] is optimal due to its stable baseline current and significant\ntranslocation signal. Subsequently, different concentrations of ILs,\nmodification durations, and nanopore sizes were examined to optimize\nthe nanopore sensing conditions. Meanwhile, the ion current rectification\nphenomenon was analyzed using a finite element simulation. Furthermore,\nDNA translocation experiments with and without IL modification were\nconducted. It was found that the normalized average translocation\namplitude of DNA with ILs showed a 2.1-fold enhancement and the average\ntranslocation time showed a 1.7-fold increase compared to that without\nILs. Meanwhile, the proportion of partially folded and knotted events\nwas significantly reduced, with knotted events approaching zero. Finally,\nan intriguing spike current enhancement phenomenon was observed. Employing\nILs for DNA translocation modification can effectively decelerate\nthe translocation speed, enhance SNR, reduce folding rates, and consequently\nadvance high-precision DNA detection technology.