Enhanced diffusion by binding to the crosslinks of a polymer gel

Katharina Ribbeck

Creating a selective gel that filters particles based on their interactions is a major goal of nanotechnology, with far-reaching implications from drug delivery to controlling assembly pathways. However, this is particularly difficult when the particles are larger than the gel’s characteristic mesh size because such particles cannot passively pass through the gel. Ribbeck (IRG II) and Brenner (Harvard University MRSEC, IRG II) used repeating units of the nuclear pore as a model system and identified an equilibrium mechanism where crosslink binding dynamics are affected by interacting particles such that particle diffusion is enhanced, enabling particles larger than the meshsize to selectively penetrate through a hydrogel. In addition to revealing specific design rules for manufacturing selective gels, our results have the potential to explain the origin of selective permeability in certain biological materials, including the nuclear pore complex.

Figure shows that specific binding to the crosslinks of a polymer gel can result in enhanced diffusion of a particle.

Polymer Science at the Boston Museum of Science

Each summer, Professor Ribbeck and a group of students from MIT MRSEC teach lessons on polymer science to children as part of the Boston Museum of Science’s Grossology summer camp. In this hands-on  course children obtain samples of gels with different properties to explore and learn basic phenomena in polymer science.

Photos of children in the Boston Museum of Science’s summer camp “Grossology”, learning about Polymer Science taught by the Ribbeck lab and MRSEC students.

Goodrich, C. P., Brenner, M. P., and Ribbeck, K. “Enhanced Diffusion by Binding to the Crosslinks of a Polymer Gel.” Nature Communications, 9(1), 2018. <doi:10.1038/s41467-018-06851-5>