Solid-state nanopores are single molecule sensors that measure changes in ionic current as charged polymers such as DNA pass through. Here, we present comprehensive experiments on the length, voltage and salt dependence of the frequency of double-stranded DNA translocations through conical quartz nanopores with mean opening diameter 15 nm. We observe an entropic barrier limited, length dependent translocation frequency at 4M LiCl salt concentration and a drift-dominated, length independent translocation frequency at 1M KCl salt concentration. These observations are described by a unifying convection-diffusion equation which includes the contribution of an entropic barrier for polymer entry.

翻译：固态纳米粒子是单分子感应器,用来测量充电聚合物(如DNA通过)在电离电流中的变化。在这里,我们通过二次冲压式DNA转移频率的长度、电压和盐依赖性进行全面实验,平均直径为15纳米孔径,通过二次冲压式转基因频率的长度、电压和盐依赖性进行试验,我们观测到在4M LiCl盐浓度和1M KCl盐浓度的漂控式、长度独立的流控式转移频率上一个有限、长依赖性转移频率的孔屏障。这些观测结果通过一个统一的对流式扩散方程式进行描述,其中包括聚合物进入的诱变屏障。