Procedure to construct a multi-scale coarse-grained model of DNA-coated colloids from experimental data

TL;DR

This paper introduces a transferable multi-scale coarse-grained model for DNA-coated colloids based solely on experimental data, accurately predicting their phase behavior and structural properties, and highlighting limitations of pairwise interaction assumptions.

Contribution

The authors develop a novel, experimentally grounded coarse-grained model for DNA-coated colloids that improves prediction accuracy over traditional pairwise additive approaches.

Findings

Model accurately predicts equilibrium structure and melting temperature.

Pairwise additivity assumptions can lead to incorrect phase behavior predictions.

Discrepancies due to limited data on DNA persistence length.

Abstract

We present a quantitative, multi-scale coarse-grained model of DNA coated colloids. The parameters of this model are transferable and are solely based on experimental data. As a test case, we focus on nano-sized colloids carrying single-stranded DNA strands of length comparable to the colloids' size. We show that in this regime, the common theoretical approach of assuming pairwise additivity of the colloidal pair interactions leads to quantitatively and sometimes even qualitatively wrong predictions of the phase behaviour of DNA-grafted colloids. Comparing to experimental data, we find that our coarse-grained model correctly predicts the equilibrium structure and melting temperature of the formed solids. Due to limited experimental information on the persistence length of single-stranded DNA, some quantitative discrepancies are found in the prediction of spatial quantities. With the availability of better experimental data, the present approach provides a path for the rational design of DNA-functionalised building blocks that can self-assemble in complex, three-dimensional structures.