Tuning Peptide Scaffold Stiffness Improves Dopaminergic Neuron Survival for Parkinson's Research

5 mol% azaG substitution increased nanofiber persistence length 5-fold. Scaffold bioactivity toward iPSC-derived dopaminergic neurons was enhanced by persistence length independently of bulk storage modulus, improving neuron survival and tyrosine hydroxylase expression.

In vitro study. Peptide amphiphiles with aza-glycine substitutions self-assembled into nanofibers. Persistence length measured by microscopy, diffusion by FRAP, bulk modulus by rheology. Bioactivity tested with iPSC-derived dopaminergic neurons in 3D hydrogel culture.

Parkinson's disease destroys dopaminergic neurons. Growing replacement neurons on optimized peptide scaffolds could advance cell therapy approaches. The finding that cells sense nanoscale rather than bulk stiffness changes how we design biomaterials for neural regeneration.

This study reveals a key principle in biomaterials: cells sense mechanical properties at the nanofiber scale, not just the bulk gel level. This insight could transform how peptide scaffolds are designed for neural and other tissue engineering applications.

In vitro iPSC-derived neuron culture only. No in vivo testing for Parkinson's application. Long-term neuron functionality and scaffold degradation not assessed. Manufacturing azaG-containing peptides may be more complex.