Nanoparticle Transport Dynamics in Synthetic Mucin Hydrogel Networks

This study investigates the diffusion behavior of gold nanorods within a synthetic mucin hydrogel designed to replicate the physiological and viscoelastic properties of lung mucus. Hydrogels were prepared using bovine submaxillary mucin (BSM) at varying concentrations and cross-linked to induce gelation. A known mucolytic agent, N-acetylcysteine (NAC), was introduced into the hydrogel to disrupt its disulfide bonds, thus breaking down the hydrogel network. Two-photon fluorescence correlation spectroscopy provided insights into the rotational and translational dynamics of the anisotropic particles, both before and after NAC treatment. The rotational diffusion coefficients of the nanorods decreased as mucin concentration increased, likely due to the increased viscosity and network density of the hydrogel. In the gelled BSM, a significant increase in rotational diffusion coefficient was observed, which subsequently decreased upon NAC addition. Time-dependent diffusion measurements revealed that NAC had minimal impact on the translational diffusion coefficients, though a general decrease in the rotational diffusion coefficients was observed. These results give us a more profound understanding of how these nanoparticles diffuse within the body's respiratory tract, particularly in the mucus linings. The research is supported by NSF grant no: CBET- 2115827.