In this paper, we have investigated the interactions between alpha-synuclein fibrils at different pH values and how this relates to hydrogel formation and gel properties. Using a combination of rheology, small-angle X-ray scattering, Raman spectroscopy, and cryo-transmission electron microscopy (cryo-TEM) experiments, we have been able to investigate the relationship between protein net charge, fibril-fibril interactions, and hydrogel properties, and have explored the potential for alpha-synuclein to form hydrogels at various conditions. We have found that alpha-synuclein can form hydrogels at lower concentrations (50-300 mu M) and over a wider pH range (6.0-7.5) than previously reported. Over this pH range and at 300 mu M, the fibril network is electrostatically stabilized. Decreasing the pH to 5.5 results in the precipitation of fibrils. A maximum in gel stiffness was observed at pH 6.5 (similar to 1300 Pa), which indicates that significant attractive interactions operate at this pH and cause an increase in the density of hydrophobic contacts between the otherwise negatively charged fibrils. We conclude that fibril-fibril interactions under these conditions involve both long-range electrostatic repulsion and a short-range hydrophobic attractive (sticky) component. These results may provide a basis for potential applications and add to the understanding of amyloids.