Self-replicating colloidal clusters

Abstract

We construct schemes for self-replicating clusters of spherical particles, validated with computer simulations in a finite-temperature heat bath. Each particle has stickers uniformly distributed over its surface, and the rules for self-replication are encoded into the specificity and strength of interactions. Geometrical constraints imply that a compact cluster can copy itself only with help of a catalyst, a smaller cluster that increases the surface area to form a template. Replication efficiency requires optimizing interaction energies to destabilize all kinetic traps along the reaction pathway, as well as initiating a trigger event that specifies when the new cluster disassociates from its parent. Although there is a reasonably wide parameter range for self-replication, there is a subtle balance between the speed of the reaction, and the error rate. As a proof of principle, we construct interactions that self-replicate an octahedron, requiring a two-particle dimer for a catalyst. The resulting selfreplication scheme is a hypercycle, and computer simulations confirm the exponential growth of both octahedron and catalyst replicas.