Alexander Kai Buell, PhD, is a professor of protein biophysics at the Technical University of Denmark, where his research is focused on pathological protein aggregation. As a doctoral student in Cambridge, he developed biosensor assays for accurately measuring the growth rates of amyloid fibrils. For his postdoctoral work, also in Cambridge, he focused on the aggregation of alpha-synuclein, a hallmark of Parkinson's disease, and he was the first to describe an autocatalytic mechanism through which amyloid fibrils of alpha-synuclein can multiply and proliferate. As an assistant professor in Düsseldorf (2015-2019), he has continued to study the mechanism of alpha-synuclein aggregation, and his group has presented the first available evidence that the process of secondary nucleation of a disease-related protein does not propagate the structural characteristics of the parent fibril.