Molecules in the 4th dimension

The movement within supramolecular assemblies is critical to their biological activity, including their ability to regenerate cartilage and repair spinal cord damage. A new finding suggests that scientists designing systems for medical use should consider molecules’ behavior beyond the three physical dimensions of space. “The fourth dimension is time. It’s not just the three-dimensional structure but what molecules are doing in time,” said Samuel I. Stupp , a chemist at Northwestern University who presented the work last week at the American Chemical Society’s Fall 2024 meeting. Stupp has been working on systems for regenerative medicine for more than 2 decades . His lab’s system uses peptide amphiphiles—molecules with a hydrophilic peptide on one end and a hydrophobic alkyl chain on the other. These molecules assemble into fibers that Stupp’s group has been exploring as a way to treat lost cartilage, repair spinal cord injuries, and grow bone in spinal fusion.