# Linker-mediated self-assembly of mobile DNA-coated colloids

## TL;DR

This paper introduces a novel system of mobile DNA-coated colloids bridged by free DNA linkers, enabling programmable self-assembly with potential for precise material construction, and develops a mean-field theory to analyze their interactions.

## Contribution

It proposes an innovative linker-mediated mobile DNA-coated colloid system and formulates a mean-field theory to calculate their effective interactions considering linker entropy.

## Key findings

- Linker concentration influences colloidal interactions.
- Strong binding makes linker entropy dominant.
- Theoretical framework aids design of programmable materials.

## Abstract

Developing construction methods of materials tailored for given applications with absolute control over building block placement poses an immense challenge. DNA-coated colloids offer the possibility of realising programmable self-assembly, which, in principle, can assemble almost any structure in equilibrium, but remains challenging experimentally. Here, we propose an innovative system of linker-mediated mobile DNA-coated colloids (mDNACCs), in which mDNACCs are bridged by the free DNA linkers in solution, whose two single-stranded DNA tails can bind with specific single-stranded DNA receptors of complementary sequence coated on colloids. We formulate a mean-field theory efficiently calculating the effective interaction between mDNACCs, where the entropy of DNA linkers plays a nontrivial role. Particularly, when the binding between free DNA linkers in solution and the corresponding receptors on mDNACCs is strong, the linker-mediated colloidal interaction is determined by the linker entropy depending on the linker concentration.