DNA Translocation Governed by Interactions with Solid-State Nanopores
DNA Translocation Governed by Interactions with Solid-State Nanopores
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DOI：
10.1529/biophysj.108.140475
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发表时间：
2008-11-15
影响因子：
3.4
通讯作者：
Meller, Amit
中科院分区：
文献类型：
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作者：
Wanunu, Meni;Sutin, Jason;Meller, Amit
我们研究了单个DNA分子通过直径范围为2.7-5 nm的固态纳米孔的电压驱动易位动力学。我们的研究揭示了一个数量级的增加易位时间时，孔径从5到2.7 nm，和陡峭的温度依赖性，近三倍大于预期，如果动态由粘性阻力。如先前预测的相互作用为主的易位过程中，我们观察到指数电压依赖于易位时间。平均易位时间与DNA长度的比例由两个幂律：对于短的DNA分子，在150-3500 bp的范围内，我们发现指数为1.40，而对于较长的分子，指数为2.28占主导地位。令人惊讶的是，我们发现了一个过渡的离子电流的部分被DNA阻断，从一个长度无关的制度短的DNA分子的制度，其中较长的DNA，更多的电流被阻止。温度依赖性的研究表明，增加DNA长度，额外的相互作用是负责较慢的DNA动力学。我们的研究结果可以合理化考虑DNA/孔的相互作用作为决定DNA在小孔中的易位动力学的主要因素。这些相互作用显著地减慢了移位速率，使得能够实现比用较大孔观察到的时间分辨率更高的时间分辨率。这些发现揭示了DNA在小孔中的传输特性，与未来的纳米孔应用相关，例如DNA测序和基因分型。
We investigate the voltage-driven translocation dynamics of individual DNA molecules through solid-state nanopores in the diameter range 2.7-5 nm. Our studies reveal an order of magnitude increase in the translocation times when the pore diameter is decreased from 5 to 2.7 nm, and steep temperature dependence, nearly threefold larger than would be expected if the dynamics were governed by viscous drag. As previously predicted for an interaction-dominated translocation process, we observe exponential voltage dependence on translocation times. Mean translocation times scale with DNA length by two power laws: for short DNA molecules, in the range 150-3500 bp, we find an exponent of 1.40, whereas for longer molecules, an exponent of 2.28 dominates. Surprisingly, we find a transition in the fraction of ion current blocked by DNA, from a length-independent regime for short DNA molecules to a regime where the longer the DNA, the more current is blocked. Temperature dependence studies reveal that for increasing DNA lengths, additional interactions are responsible for the slower DNA dynamics. Our results can be rationalized by considering DNA/pore interactions as the predominant factor determining DNA translocation dynamics in small pores. These interactions markedly slow down the translocation rate, enabling higher temporal resolution than observed with larger pores. These findings shed light on the transport properties of DNA in small pores, relevant for future nanopore applications, such as DNA sequencing and genotyping.