Conformational Nature of DNA-Grafted Chains on Spherical Gold Nanoparticles
JF Douglas and FW Starr and F Vargas-Lara, VIII INTERNATIONAL CONFERENCE ON TIMES OF POLYMERS AND COMPOSITES: FROM AEROSPACE TO NANOTECHNOLOGY, 1736, UNSP 020081 (2016).
We investigate the conformational state of a simple, coarse-grained molecular model for single-stranded DNA chains (ssDNA) grafted onto spherical symmetric gold nanoparticles (NPs) and of the grafted layer as a whole by molecular dynamic simulations. In particular, we compare the radius of gyration (R-g) of an individual grafted chain to its value in solution and we use path-integration to estimate the change delta R-h of the hydrodynamic radius of ssDNA-grafted NPs (R-h) from the hydrodynamic radius of the bare gold NP core (R = 5.0 nm) for a range of grafted chains (N), chain lengths (L), and persistence lengths (l(p)) relevant to experimental studies of these NPs. We find the ssDNA chain size is not greatly perturbed from its free solution value so that the molecular cartoon of a brush-like layer involving highly extended ssDNA chains is an unrealistic model of the interfacial structure of ssDNA-grafted NPs under the solution conditions normally investigated.
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