Revisiting Ronit's Reversible Game-Changing Hydrogel Research
Imagine you are playing softball with some friends at a neighborhood field. You’re up to bat, you swing and connect and everyone cheers you on for your homerun. But the ball has landed beyond the outfield, just behind another fence. You are able to put your hand through the fence bars and reach the ball, but the ball is too large to fit through. If only it could somewhat disassemble – rearrange it’s composition and shape just enough to fit through the bars and then go back to being a regular softball.
In essence, this is the concept behind Ronit Freeman’s 2018 study, titled Reversible self-assembly of superstructured networks (Science, 2018, Freeman et. al), only on a much, much smaller scale. The abstract of the paper reads:
Soft structures in nature, such as protein assemblies, can organize reversibility into functional and often hierarchical architectures through noncovalent interactions. Moleculary encoding this dynamic capability in synthetic materials has remained an elusive goal. We report on hydrogels of peptide-DNA conjugates and peptides that organize into superstructures of intertwined filaments that disassemble upon the addition of molecules or changes in charge density.
As you can see in the beautiful image to the left, the darker purple strands are much more densely wound together than the rest of the network. These bundled strands are able to dissipate and re-configure based on a trigger mechanism. These bundles can form rigid strands, collapse into a tangled network, and re-bundle into rigid structures. This research is foundational to the groundbreaking work with biomimicry, synthetic cells, self-assembly, therapeutics and drug delivery systems that the Freeman Lab develops.
Back to our softball, densely filled with cork and rubber cannot be squeezed to fit through the fence. But if the spatial distribution of the ball’s interior could become less dense, then perhaps the ball might be able warp its shape just enough to fit through the fence and then tighten and restructure back into the density we need to play ball.
While retrieving our softball this easily would be good news, the really exciting potential of this discovery is the ability to make transformations in astrocytes linked to brain and spinal cord injuries, as well as neurological diseases.
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Reversible self-assembly of superstructured networks
R Freeman, M Han, Z Álvarez, JA Lewis, JR Wester, N Stephanopoulos, …
Science, 2018
Uncovering supramolecular chirality codes for the design of tunable biomaterials
Stephen J. Klawa, Michelle Lee, Kyle D. Riker, Tengyue Jian, Qunzhao Wang, Yuan Gao, Margaret L. Daly, Shreeya Bhonge, W. Seth Childers, Toluope O. Omosun, Anil K. Mehta, David G. Lynn, Ronit Freeman
Nature Communications, 2024