Dynamics of Anisotropic Nanoparticles Within Model Homogenous Hydrogels

Recently, it has been experimentally shown that nanorods, in comparison to chemically identical spheres, exhibit increased diffusion in mucus, the interstitial matrix of tumors and in polyacrylamide spheroids. Creating a model system where the nanoparticle confinement can be systematically varied is imperative in identifying key length scales for the enhanced dynamics of nanorods compared to their spherical counterparts. Using single particle tracking to examine the dynamics of quantum rods with increasing probe anisotropy during the gelation of homogenous hydrogels, we can examine the dynamics of the rods in response to the changing local environment. In this study, the diameter of the rods is comparable to the final mesh size, but the lengths of the rods are larger than the final mesh size. The difference between spherical and anisotropic probe dynamics for particles with comparable diameters during this dynamic confinement process is also evaluated. This work offers important insights for predicting and controlling nanoparticle dynamics in gels, applicable to drug delivery and nanoscale filtration.