Hydrodynamic Radius Fluctuations in Model DNA-Grafted Nanoparticles
Luis Fernando Vargas Lara, Francis W. Starr, Jack F. Douglas
We utilize molecular dynamics simulations (MD) and the path-integration program ZENO to quantify hydrodynamic radius (Rh) fluctuations of spherical symmetric gold nanoparticles (NPs) decorated with single-stranded DNA chains (ssDNA). In particular, we explore the e effect of varying the sssDNA-grafted NPs structural parameters such as the chain length (L), chain persistence length (lp), NP core size (R), and the number of chains (N) attached to the nanoparticle core. We determine Rh fluctuations by calculating its standard deviation (\sigma_Rh ) of an ensemble of ssDNA-grafted NPs configurations generated by MD. For the parameter space explored in this manuscript, \sigma_Rh shows a peak value as a function of N, whose height depends on L, lp and R and whose broadness depends on R. These results are relevant to understanding fluctuation-induced interactions among these NPs and macromolecules such as proteins.