Self-assembly of biomolecules has attracted increasing interests for fabrication of nano- and micro-scaled biomaterials. In particular, designed peptides that self-assemble into nanofibers can form hydrogels and be utilized as biomaterial scaffolds for cell engineering with biocompatibility and biodegradability. Designed peptides have advantages in modulating molecular assembly and introducing functionality.1
We have found that de novo designed short peptides, Y9 (Ac-YKYEYKYEY-NH2), self-assembled into highly-networked fibrillar structures with beta-sheet conformations in aqueous solution. In addition, we have constructed self-assembling peptide nanofibers with responsive ability to calcium ion (Ca2+) to control assembled structures. A various number of Glu residues were conjugated to the N termini of Y9 as a Ca2+ responsive site (EnY9). Moreover, the cell-adhesive and -differentiation peptide units (RGDS and IKVAV) were introduced to the C termini of E1Y9 to functionalize as cell-adhesive scaffolds (E1Y9-RGDS/-IKVAV). In the presence of CaCl2, EnY9 and E1Y9-RGDS/-IKVAV peptides assembled into wider structures than Y9, and formed stable hydrogels. On the hydrogels composed of E1Y9, E1Y9-RGDS/-IKVAV, 3T3-L1/PC-12 cells were cultured more than 7 days without any toxicity. The self-assembling peptide materials based on the Y9 peptide are useful for cell engineering as novel scaffolds.