 The spheres then join together spontaneously to form linear chains, which evolve into mature amyloid fibers.The formation of these linear chains appears to be driven by the development of an electrostatic dipole in each of the colloidal spheres strong enough to overcome coulomb repulsion.This suggests a possible mechanism by which alpha sheet may promote amyloid aggregation; the peptide bond has a relatively large intrinsic electrostatic dipole, but normally the dipoles of nearby bonds cancel each other out.