The coupling of rotational and translational dynamics for rapid diffusion of nanorods in macromolecular networks.

The rod-like viruses show anomalously rapid diffusion in bio-tissue networks originated from the rotation-facilitated transportation; however, the experimental investigation of the correlation of the rotational and translational dynamics is still in blank. Herein, typical rod-like and spherical gold nanoparticles (NPs) are dispersed in the classical Tetra-PEG gels, respectively, as model systems for light scattering studies. The contributions from translational and rotational diffusive dynamics, and network fluctuation dynamics can be well-resolved and the stretch exponent of rotational dynamics at 0.25 is proven to be the fingerprint for the coupled rotational and translational dynamics of nanorods. The rotation facilitated re-orientation finally leads to the fast transportation of nanorods. The discoveries are confirmed to be valid for rod-like biomacromolecule systems by studying the diffusive dynamics of Tobacco mosaic virus in gels. The work can be inspiring for the development of protocols to prevent infection of microorganism and regulate the transportation of nano-medicines.