Diffusivity of DNA-Linked Colloidal Chains

Stable linear colloidal chains can be formed by linking magnetic colloidal particles with oligonucleotides. These DNA-linked paramagnetic particle chains form a model bead-spring-bead system with worm-like chain behavior.  The bending rigidity, or persistence length, of a chain can be determined by monitoring its thermal fluctuations and performing a Fourier mode analysis of their bending motion.  Here we will demonstrate how the persistence length of the chains can be tuned by changing the rigidity of the linkers connecting them.  In particular, we will demonstrate how a stiffer double-stranded linkage versus single-stranded lead to chains with better stability and greater flexibility.