Meshing complex macro-scale objects into self-assembling bricks

Abstract

Self-assembly provides an information-economical route to the fabrication of objects at virtually all scales. However, there is no known algorithm to program self-assembly in macro-scale, solid, complex 3D objects. Here such an algorithm is described, which is inspired by the molecular assembly of DNA, and based on bricks designed by tetrahedral meshing of arbitrary objects. Assembly rules are encoded by topographic cues imprinted on brick faces while attraction between bricks is provided by embedded magnets. The bricks can then be mixed in a container and agitated, leading to properly assembled objects at high yields and zero errors. The system and its assembly dynamics were characterized by video and audio analysis, enabling the precise time- and space-resolved characterization of its performance and accuracy. Improved designs inspired by our system could lead to successful implementation of self-assembly at the macro-scale, allowing rapid, on-demand fabrication of objects without the need for assembly lines.

Macroscopic equivalence for microscopic motion in a turbulence driven three-dimensional self-assembly reactor

“…Hacohen et al [26] demonstrated DNA-inspired patterned bricks with embedded magnets, self-assembling into a programmed structure, but report gravity bias. Stambaugh et al [27] reported self-assembled 2D structures of centimetersized spherical particles with internal magnets that were shaken vertically, and observed different resulting structures that were based on particle concentration and magnet shape.…”

Observing magnetic objects in fluids

“…The simulated results of these works show qualitative correspondence with experimental data obtained from systems of macroscopic particles. Among available options (Kudrolli, 2004;Kumar et al, 2015;Ojha et al, 2004), orbital shaking is a useful agitation method for macroscopic setups to study the dynamics and interactions of granular matter (Bhalla et al, 2014;Cademartiri et al, 2012;Grünwald et al, 2016;Hacohen et al, 2015;Tricard et al, 2013Tricard et al, , 2015. The statistics of the motion that orbital shaking imparts to solid, in-plane bound particles was however not characterised to date.…”

“…Macroscopic self-assembly processes on a centimetre scale are dominated by twodimensional structures, where mechanical shaking is the most widely used source of disturbing energy. Hacohen et al (2015) demonstrated DNA-inspired patterned bricks with embedded magnets, self-assembling into a programmed structure, but report gravity bias. Stambaugh et al (2003) reported self-assembled 2D structures of centimetre-sized spherical particles with internal magnets that were shaken vertically, and observed different resulting structures that were based on particle concentration and magnet shape.…”

“…B: Centimetre-sized floating magnetic cubes self-assemble in patterns when shaken (Miyashita et al, 2009). C: Uniquely patterned bricks assemble into a product through shaking (Hacohen et al, 2015). D: Turbulence driven three-dimensional self-assembly creates line structures out of centimetre-sized magnetic cubes (Ilievski et al, 2011b).…”

“…They quantified the aggregation characteristics and showed that rounded particles assemble faster than squared ones and that the early stages of the aggregation pattern are crucially influential to the rest of the process. Hacohen et al (2015) investigated programmed assembly of macroscopic magnetic bricks by patterning the sides of tetrahedrons, which assemble after agitation. These works are primarily two-dimensional in nature, however, and are not representative for true three-dimensional systems.…”