Hydrogel Formation by an Aromatic Analogue of a β-Amyloid Fragment, Aβ16-22: A Scaffold for 3D Cell Culture

Abstract

A short 7-residue stretch from β-amyloid, Aβ16-22 (Ac-KLVFFAE-am), yields typical amyloid-like fibrils at neutral pH. The Phe-Phe cassette present in the peptide is believed to be critical for its self-assembly. We report that the aromatic analogue Aβ16-22(F20Y) forms self-supporting soft gels at concentrations ≥2 mM even though the end-capped parent peptide does not form hydrogel up to 20 mM (1.8% w/w) concentration. The hydrogel is made up of distinct amyloid-like fibers. The storage modulus of 20 mM gel is ∼3-5-fold higher than the loss modulus in the 2-3000 rad/s angular frequency range, indicating distinct elastic properties. The hydrogel supports the growth of rat pancreatic cells (RIN-5F), human embryonic kidney cells (HEK-293), baby hamster kidney cells (BHK-21), and human neuroblastoma cells (IMR-32). The cells grow in clusters as is anticipated in a three-dimensional matrix. The rat pancreatic cells produced insulin, suggesting that they are functional inside the gel.