Center for Soft Condensed Matter Physics & Interdisciplinary Research, School of Physical Science and Technology, Soochow University, Suzhou 215006, China.
Phys Chem Chem Phys. 2019 Feb 20;21(8):4487-4493. doi: 10.1039/c8cp05976d.
Folding and unfolding of a chain structure are often manipulated in experiments by tuning the pH, temperature, single-molecule forces or shear fields. Here, we carry out Brownian dynamics simulations to explore the behavior of a single self-attracting chain in a suspension of self-propelling particles (SPPs). As the propelling force increases, the globule-stretch (G-S) transition of the chain occurs due to the enhanced disturbance from the SPPs. Two distinct mechanisms of the transition in the limits of low and high rotational diffusion rates of SPPs have been observed: shear-induced stretching at a low rate and collision-induced melting at a high rate. The G-S and S-G (stretch-globule) curves form a hysteresis loop at the low rate, while they merge at the high rate. Besides, we find that two competing effects result in a non-monotonic dependence of the G-S transition on SPP density at the low rate. Our results suggest an alternative approach to manipulating the folding and unfolding of (bio)polymers by utilizing active agents.
折叠和展开链结构通常通过调节 pH 值、温度、单分子力或剪切场在实验中进行操纵。在这里，我们进行了布朗动力学模拟，以研究在自推进粒子 (SPP) 悬浮液中单链自吸引链的行为。随着推进力的增加，由于 SPP 引起的干扰增强，链发生了球晶-伸展 (G-S) 转变。在 SPP 旋转扩散率低和高的极限下，观察到两种不同的转变机制：低速率下的剪切诱导拉伸和高速率下的碰撞诱导熔融。在低速率下，G-S 和 S-G（伸展-球晶）曲线形成滞后环，而在高速率下它们合并。此外，我们发现两种竞争效应导致 G-S 转变对 SPP 密度的依赖关系在低速率下呈非单调变化。我们的结果表明，通过利用活性试剂，操纵（生物）聚合物的折叠和展开有了一种替代方法。
