Electric-Field-Driven Trapping of Polyelectrolytes in Needle-like Backfolded States
Electric-Field-Driven Trapping of Polyelectrolytes in Needle-like Backfolded States
复制标题
电场驱动捕获针状反折叠状态的聚电解质
作者：
A. Suma;M. Di Stefano;C. Micheletti
具有强反离子耦合的聚电解质在低电场下是紧凑的，但在高电场下会变成细长形式。迄今为止，我们对纳米操纵实验和关于紧凑态和扩展态之间的转变机制的理论知之甚少。在这里，我们使用分别在约 20000 和 80000 个带电粒子的盐缓冲液中对 1000 和 1500 个单体的粗粒聚电解质链进行分子动力学模拟，系统地解决了这种不平衡转化问题。我们发现，只有一半的轨迹从紧凑到拉长的过渡是平滑和快速的。在另一半中，由于向后折叠的针状状态的形成，伸长被卡住了一半。这些状态是以前没有预见到的，它们的寿命比链的弛豫时间大几个数量级，并且应该可以用当前的单分子实验装置检测到。
Polyelectrolytes with strong counterion couplings are compact at low electric fields but switch to elongated forms at high ones. As yet, little is known from both nanomanipulation experiments and theory about the transition mechanisms between compact and extended states. Here, we systematically address this out-of-equilibrium conversion using molecular dynamics simulations of coarse-grained polyelectrolyte chains of 1000 and 1500 monomers in a salt buffer of about 20 000 and 80 000 charged particles, respectively. We find that compact-to-elongated transitions are smooth and fast in only half of the trajectories. In the other half, the elongation is jammed halfway by the formation of backfolded, needle-like states. These states, which have not been envisioned before, have lifetimes that are orders of magnitude larger than the chain’s relaxation time and ought to be detectable with current single-molecule experimental setups.
登录
查看更多内容
影响因子：
3.4
作者：
Janmey PA;Slochower DR;Wang YH;Wen Q;Cēbers A
通讯作者：
Cēbers A
影响因子：
10.8
作者：
Levy SL;Mannion JT;Cheng J;Reccius CH;Craighead HG
通讯作者：
Craighead HG
影响因子：
10.8
作者：
Heng, JB;Aksimentiev, A;Timp, G
通讯作者：
Timp, G
DOI：
10.1073/pnas.96.2.453
发表时间：
1999-01-19
影响因子：
11.1
作者：
Gurrieri, S;Smith, SB;Bustamante, C
通讯作者：
Bustamante, C
影响因子：
10.8
作者：
Laohakunakorn, Nadanai;Ghosal, Sandip;Keyser, Ulrich F.
通讯作者：
Keyser, Ulrich F.