Neural differentiation directed by self-assembling peptide scaffolds presenting laminin-derived epitopes.

We prepared biofunctionalized matrices for cell growth using (RADA)(3)IKVAV(RADA)(3) ((Arg-Ala-Asp-Ala)(3)-Ile-Lys-Val-Ala-Val-(Arg-Ala-Asp-Ala)(3)) and (RADA)(4)IKVAV ((Arg-Ala-Asp-Ala)(4)-Ile-Lys-Val-Ala-Val), self-assembling peptides with a laminin-derived sequence inserted between and attached terminally to the repeats of RADA, respectively. The material-cell interactions were investigated with PC12, a cell line commonly used as a model for studying neural differentiation. The behavior of PC12 and especially the neural differentiation was guided by the presence of IKVAV. Furthermore, the cell-material interactions were dependent on the culture dimensionality and the position of IKVAV in the self-assembling peptide template. In the two-dimensional (2-D) culture, matrices containing IKVAV stimulated significantly longer neurite outgrowths from PC12 cells than did (RADA)(4). More pronounced effect was observed in (RADA)(3)IKVAV(RADA)(3) than in (RADA)(4)IKVAV. In the three-dimensional (3-D) culture, neurite outgrowth was not observed in the biofunctionalized matrices. Instead, cells displayed higher proliferation rate and survived longer culture time than in the 2-D culture, with such enhancement being most significant in (RADA)(3)IKVAV(RADA)(3.) Despite the lack of differentiation phenotype, the cells grown in 3-D biofunctionalized matrices were primed for differentiation, as evident by enhanced neurite outgrowth, increased neurite networking, and up-regulated expression of differentiation markers upon their reintroduction to the 2-D culture condition on petri dish. With the ease of incorporating biofunctional epitopes, and the flexibility to support either 2-D or 3-D culture, self-assembling peptides provide versatile scaffolds to study the multiple facets of biomaterial-cell interactions.