Strategy for Designing Self‐Assembling Peptides to Prepare Transparent Nanofiber Hydrogel at Neutral pH

This study examined the formation of nanofiber hydrogels at neutral pH for 16 types of peptides with different net charges, hydrophobicities, and degrees of polymerization. The peptides formed various hydrogels depending on the arrangement of charged amino acids in the antiparallel β‐sheet structure. Circular dichroism (CD) measurement, atomic force microscopy (AFM), visible light spectroscopy, and dynamic viscoelasticity measurement showed that the formation of transparent nanofiber hydrogels in peptides requires at least 2 additional positively or negatively charged amino acids per peptide. When designing the amino acid sequence, it is important to consider both the net charge and position of the charged amino acids, and it should be ensured that basic amino acids do not face other basic ones in the antiparallel β‐sheet structure. Peptides that had charged amino acids clustered at the center of the nanofiber formed rigid gels.