Shape Anisotropy Enhances Nanoparticle Dynamics in Nearly Homogeneous Hydrogels
Katie A. Rose, Natalie Gogotsi, Jonathan H. Galarraga, Jason A. Burdick, Christopher B. Murray, Daeyeon Lee, Russell J. Composto
Abstract
Single particle tracking is used to investigate the effect of nanoparticle shape anisotropy on dynamics. The mean squared displacements of poly(ethylene glycol) (PEG)-functionalized quantum dot (QD) and quantum rod (QR) probes of similar diameters are examined during the gelation of a tetra-poly(ethylene glycol) (tetra-PEG) hydrogel. At early times prior to the gel time (tgel), QDs exhibit greater mobility than their QR counterparts. However, as gelation proceeds, QRs exhibit increased dynamics compared to QDs, suggesting enhanced rod dynamics in increasingly confined networks. Potential mechanisms are discussed, including the influence of rotational dynamics and the increased parallel diffusion of rods in confined systems. This study provides insights into developing nanoparticle probes of different shape anisotropy, with particular importance for their use in drug delivery and other biomedical applications.