In mice with a spinal cord injury, mixing materials including bioactive sequences formed a polymer meshwork that improved axon regrowth, angiogenesis, and neuronal cell survival. The study points to opportunities for specially controlled supramolecular polymers.
The design of materials to encourage the repair of tissue after injury is a long-standing goal of regenerative medicine. Particularly as relates to spinal cord injury, scientists have focused on designing synthetic mimics of the extracellular matrix (ECM), a vital component of all tissues. Supramolecular polymers-;a promising class of materials that self-assemble into fibrous materials-;can act as simple but tailored mimics of the ECM.
Z Álvarez et al. synthesized supramolecular peptide fibril scaffolds bearing two peptide sequences that promote nerve regeneration-;one that reduces glial scarring and another that promotes blood vessel formation. They tested their supramolecular peptide fibril scaffolds in a mouse model of paralyzing human spinal cord injury.
By mutating the peptide sequence of key monomers in the scaffolds, they intensified the motions of molecules within the scaffold fibrils. This resulted in notable differences in vascular growth, axonal regeneration, myelination, survival of motor neurons, reduced gliosis, and functional recovery in the mice.
"Our work demonstrates that bioactive scaffolds that physically and computationally reveal greater supramolecular motion lead to greater functional recovery from [spinal cord injury] in the murine model," the authors write.
"Álvarez et al. add to our understanding of how supramolecular polymers efficiently interact with neural cells and promote regeneration, highlighting the importance of supramolecular assembly dynamics," said Jonathan P. Wojciechowski and Molly M. Stevens in a related Perspective.
Álvarez, Z., et al. (2021) Bioactive Scaffolds with Enhanced Supramolecular Motion Promote Recovery from Spinal Cord Injury. Science. doi.org/10.1126/science.abh3602.