J Phys Chem B. 2018 Oct 25;122(42):9815-9825. doi: 10.1021/acs.jpcb.8b08096. Epub 2018 Oct 11.
Addressable self-assembly is the formation of a target structure from a set of unique molecular or colloidal building blocks, each of which occupies a defined location in the target. The requirement that each type of building block appears exactly once in each copy of the target introduces severe restrictions on the combinations of particles and on the pathways that lead to successful self-assembly. These restrictions can limit the efficiency of self-assembly and the final yield of the product. In particular, partially formed fragments may compete with each other if their compositions overlap, since they cannot be combined. Here, we introduce a "completability" algorithm to quantify competition between self-assembling fragments and use it to deduce general principles for suppressing the effects of fragment incompatibility in the self-assembly of small addressable clusters. Competition originates from loops in the bonding network of the target structure, but loops may be needed to provide structural rigidity and thermodynamic stability. An optimal compromise can be achieved by careful choice of bonding networks and by promoting semihierarchical pathways that rule out competition between early fragments. These concepts are illustrated in simulations of self-assembly in two contrasting addressable targets of 20 unique components each.
可寻址自组装是指由一组独特的分子或胶体构建块形成目标结构，每个构建块在目标中占据一个定义的位置。每个类型的构建块在目标的每个副本中只出现一次的要求，对粒子的组合和导致成功自组装的途径都提出了严格的限制。这些限制可能会限制自组装的效率和最终产物的产率。特别是，如果部分形成的片段的组成部分重叠，它们可能会相互竞争，因为它们不能组合。在这里，我们引入了一种“完全性”算法来量化自组装片段之间的竞争，并利用它推导出在小的可寻址簇的自组装中抑制片段不兼容性影响的一般原则。竞争源于目标结构的键合网络中的环，但环可能是提供结构刚性和热力学稳定性所必需的。通过仔细选择键合网络并促进排除早期片段之间竞争的半层次途径，可以实现最佳折衷。这些概念在对两个具有 20 个独特组件的对比性可寻址目标的模拟中得到了说明。
