Simple Quantitative Model for the Reversible Association of DNA Coated Colloids

Rémi Dreyfus, Mirjam E. Leunissen, Roujie Sha, Alexei V. Tkachenko, Nadrian C. Seeman, David J. Pine, and Paul M. Chaikin

Phys. Rev. Lett. 102, 048301 – Published 27 January 2009

Abstract

We investigate the reversible association of micrometer-sized colloids coated with complementary single-stranded DNA “sticky ends” as a function of the temperature and the sticky end coverage. We find that even a qualitative description of the dissociation transition curves requires the inclusion of an entropic cost. We develop a simple general model for this cost in terms of the configurational entropy loss due to binding and confinement of the tethered DNA between neighboring particles. With this easy-to-use model, we demonstrate for different kinds of DNA constructs quantitative control over the dissociation temperature and the sharpness of the dissociation curve, both essential properties for complex self-assembly processes.