On-chip concentration method for deoxyribonucleic acid (DNA) molecules is preconcentrating DNA molecules before analyses using nanometer-sized structures formed in a microchannel and is effective in improving the sensitivity in DNA analyses using microfluidic devices. Although accurate and predictive theoretical models of concentration profile and concentration factor in on-chip concentration can be used for designing nanostructures and optimizing conditions for concentration, there has been few studies on models. In our previous study, we presented a method of on-chip concentration of DNA molecules using a nanoslit, which is a smaller gap than the diameter of random-coiled DNA molecules. This method is based on the principle of an entropic trap, and we achieved DNA concentration by controlling the applied voltage. In this study, we developed theoretical models of concentration profile and concentration factor in on-chip concentration for DNA molecules using a nanoslit. We conducted concentration experiments of lambda DNA (λ DNA) using our fabricated chip device with a 25-nm nanoslit. The theoretical results of our models were in good agreement with these experimental results. Based on our theoretical models, we determined the optimal applied voltage to be 0.95 V for maximizing the concentration factor in λ DNA concentration by using our chip device.

芯片上的脱氧核糖核酸（DNA）分子浓缩方法是在使用微通道中形成的纳米级结构进行分析之前对DNA分子进行预浓缩，这种方法有效地提高了使用微流体装置进行DNA分析的灵敏度。尽管可以使用精确和可预测的浓度分布图和片上浓度中浓度因子的理论模型来设计纳米结构和优化浓度条件，但有关模型的研究很少。在我们先前的研究中，我们提出了一种使用纳米缝隙对芯片上的DNA分子进行浓缩的方法，该缝隙比随机缠绕的DNA分子的直径小。该方法基于熵陷阱的原理，我们通过控制施加的电压实现了DNA浓缩。在这个研究中，我们使用纳缝技术开发了芯片上浓度的浓度分布和浓度因子的理论模型。我们使用制造的带有25 nm纳米缝隙的芯片设备进行了λDNA（λDNA）的浓缩实验。我们模型的理论结果与这些实验结果非常吻合。根据我们的理论模型，我们通过使用芯片设备将最佳施加电压确定为0.95 V，以最大化λDNA浓度中的浓度因子。我们模型的理论结果与这些实验结果非常吻合。根据我们的理论模型，我们通过使用芯片设备将最佳施加电压确定为0.95 V，以最大化λDNA浓度中的浓度因子。我们模型的理论结果与这些实验结果非常吻合。根据我们的理论模型，我们通过使用芯片设备将最佳施加电压确定为0.95 V，以最大化λDNA浓度中的浓度因子。