Nanoparticles Diffusion in Hydrogels Showcased by University of British Columbia Researchers

Strategic Insights -

Scientists at the University of British Columbia have shed new light on the diffusion of nanoparticles in hydrogels, discovering that rod-like particles diffuse faster than spherical ones. The research, led by Mohammad-Reza Rokhforouz, explored the underlying physics of this phenomenon and found that the particles' aspect ratio plays a crucial role in their diffusivity. The study's findings have significant implications for the development of new materials and technologies.

Key Takeaways:

  • The researchers developed a 3D Brownian dynamics model to investigate the diffusion of rod-like nanoparticles (RNPs) in polymeric hydrogels.
  • The model predicts that RNP diffusivity increases monotonically with the aspect ratio in non-adhesive gels, in agreement with the predictions of an obstruction scaling (OS) model.
  • However, the model also reveals that RNPs experience a skewed pore-size distribution in favor of the larger pores, leading to a higher diffusivity than predicted by the OS model.
  • The anisotropy in diffusion further elevates the translational diffusivity of RNPs, resulting in a faster diffusion rate compared to spherical particles.
  • The research highlights the importance of including both steric repulsion and adhesive interactions in the model to accurately predict RNP diffusivity.

Statistics:

  • The researchers found that the RNP diffusivity can be up to 5 times higher than predicted by the OS model for higher aspect ratios.
  • The study's findings suggest that the diffusivity of RNPs increases with the aspect ratio, with a 3- to 5-fold increase observed for aspect ratios greater than 10.
  • The model predicts that the RNP diffusivity is intermediate between the purely steric and purely adhesive cases, with a stronger influence of steric repulsion in the smaller pores.
  • Overall, the research shows an even greater advantage for RNPs in terms of rapid diffusion in hydrogels than previously anticipated.

Sources:

  • Brownian dynamics simulation of the diffusion of rod-like nanoparticles in polymeric gels. Soft Matter, 2025.
  • Royal Soc Chemistry, Thomas Graham House, Science Park, Milton Rd, Cambridge CB4 0WF, Cambs, England. (www.rsc.org/)
  • Soft Matter - pubs.rsc.org/en/journals/journalissues/sm
  • The University of British Columbia, Dept. of Chemical and Biological Engineering, Vancouver, British Columbia, Canada.