Time-lapse imaging was carried out in Asylum MFP3D instrument using the MSNL probe (Bruker Corporation). First the functionalized mica surface was imaged in 10 mM sodium phosphate buffer (pH 7.0) to obtain a clean surface, then the desired amount of protein solution was added (100 nM) and imaging was carried out. On-surface aggregation was monitored by scanning the surface at one hour time intervals. The results shown in Supplementary Fig. 6B have been obtained using Nanoscope Multimode VIII system (Bruker, Santa Barbara, CA) in Peakforce mode. A small droplet of 10 nM alpha-synuclein was created under the fluid cell, then the cell was inserted into scanner head and imaging was being continued after proper alignment of the laser. The imaging was continued in the same area to monitor the changes in morphology of the aggregates.