Sarkar Debarati, Thakur Snigdha, Tao Yu-Guo, Kapral Raymond
Department of Physics, Indian Institute of Science Education and Research Bhopal, India.
Soft Matter. 2014 Dec 21;10(47):9577-84. doi: 10.1039/c4sm01941e. Epub 2014 Nov 3.
The principles that underlie the motion of colloidal particles in concentration gradients and the propulsion of chemically-powered synthetic nanomotors are used to design active polymer chains. The active chains contain catalytic and noncatalytic monomers, or beads, at the ends or elsewhere along the polymer chain. A chemical reaction at the catalytic bead produces a self-generated concentration gradient and the noncatalytic bead responds to this gradient by a diffusiophoretic mechanism that causes these two beads to move towards each other. Because of this chemotactic response, the dynamical properties of these active polymer chains are very different from their inactive counterparts. In particular, we show that ring closure and loop formation are much more rapid than those for inactive chains, which rely primarily on diffusion to bring distant portions of the chain in close proximity. The mechanism presented in this paper can be extended to other chemical systems which rely on diffusion to bring reagents into contact for reactions to occur. This study suggests the possibility that synthetic systems could make use of chemically-powered active motion or chemotaxis to effectively carry out complex transport tasks in reaction dynamics, much like those that molecular motors perform in biological systems.
用于设计活性聚合物链的原理基于胶体粒子在浓度梯度中的运动以及化学驱动的合成纳米马达的推进。活性链在聚合物链的末端或其他位置包含催化单体和非催化单体或珠子。催化珠子处的化学反应产生自生成的浓度梯度,非催化珠子通过扩散泳动机制对该梯度做出响应,使这两个珠子相互靠近移动。由于这种趋化反应,这些活性聚合物链的动力学性质与其非活性对应物有很大不同。特别地,我们表明环化和环形成比非活性链快得多,非活性链主要依靠扩散使链的远处部分靠近。本文提出的机制可扩展到其他依赖扩散使试剂接触以发生反应的化学系统。这项研究表明,合成系统有可能利用化学驱动的活性运动或趋化作用在反应动力学中有效地执行复杂的传输任务,就像分子马达在生物系统中执行的任务一样。