Authors: Giehm L, Otzen DE There is great interest in developing reproducible high-throughput screens to identify small molecular inhibitors of protein fibrillization and aggregation for possible therapy against deposition diseases such as Alzheimer's and Parkinson's (PD). We have made a methodical analysis of factors increasing the reproducibility of the fibrillization of alpha-synuclein (alphaSN), a 140 amino acid protein implicated in PD and notorious for its erratic fibrillization behaviour. Salts and polyanionic polymers do not significantly improve the quality of the assay. However, an orbital agitation mode in the plate reader is a crucial first step towards reproducible alphaSN fibrillization. Higher reproducibility is achieved by the addition of glass beads, as evaluated by th...