Self-assembly protocol design for periodic multicomponent structures

Abstract

Assembling molecular superstructures with many distinct components will allow unprecedented control over morphology at the nanoscale. Recently, this approach has been used to assemble periodic structures with precisely defined features, such as repeating arrays of pores and channels, using a large number of building blocks. Here we propose a predictive tool that allows us to optimize the nucleation and growth of unbounded, ordered structures. In what follows, we call these structures 'crystals', even though they may only be periodic in one or two dimensions. We find that the nucleation barriers and growth pathways for crystals consisting of many components exhibit generic features that are very different from those of simple crystals. To illustrate the very non-classical nature of the nucleation and growth of such structures, we study the formation of one and two-dimensional crystals with multicomponent unit cells. We find that, whilst the boundaries in the non-periodic dimensions significantly affect the stabilities of these crystals, the nucleation barriers are largely determined by the local connectivity of the associated bulk crystal and are independent of the number of distinct components in the unit cell. We predict that the self-assembly of crystals with complex morphologies can be made to follow specific pathways toward the target structure that successively incorporate key features of the three-dimensional target structure. In contrast with simple crystals, it is possible to tune the kinetics of nucleation and growth separately, thus minimizing defect formation. We show how control over self-assembly pathways can be used to optimize the kinetics of formation of extended structures with arbitrary nanoscale patterns.

Assembly of multi-flavored two-dimensional colloidal crystals

“…1–5 By tuning their pairwise interactions, nano- and microscale colloids can be assembled into a myriad of morphologies with even greater complexity than those found in atomic systems. 6,7 The vast phase space of parameters governing the mathematical form of these potential interactions can be daunting, and determining specific pair potentials that stabilize a desired structure is rarely obvious.…”

Multi-scale coarse-graining for the study of assembly pathways in DNA-brick self-assembly

“…In contrast to systems with only a few components, the only way to achieve full assembly is to use a cooling protocol, where the system first crosses the nucleation barrier to a partially formed assembly, and further cooling stabilises the full assembly. While our calculations are quantitative for a specific 334 strand SST system, a number of the basic qualitative results above are also found with simpler models [20][21][22][23][24][25] and are likely to generically hold for a wider range of target structures [8][9][10][11][12][13][14] that use the addressable SST assembly method.…”

“…More recently, this model was used to investigate strategies to optimise nucleation and growth of unbounded, periodic structures. 25 Another strand of research into addressable assembly, also using simplified models, 26 has suggested that using carefully chosen non-stoichiometric abundances of assembly components may help to mitigate aggregation and undesirable monomer starvation effects.…”

Stochastic Yield Catastrophes and Robustness in Self-Assembly

“…Second, the formation of a structure must be initiated by a nucleation event ('nucleation'). Due to cooperative or allosteric effects in binding, there might be a significant nucleation barrier [15][16][17][18][19] . Third, following nucleation, structures grow via aggregation of substructures ('growth').…”