Paper BI-TuP16
Direct Electron Beam Imaging of Proteinaceous Fibrils

Tuesday, October 31, 2017, 6:30 pm, Room Central Hall

Direct electron beam imaging method was investigated with abnormal protein assembly of amyloid fibrils. Without and with metal coating, the fast electron beam methods such like scanning electron microscope (SEM) and transmission electron microscope (TEM) were used to observe in nanoscale and compared with slow tip-probing method, atomic force microscope (AFM). As a model protein for amyloid fibril, insulin protein (15 kDa) was chosen, whose aggregation has been believed to have a relation with type II diabetes in human. The insulin amyloid fibrils have grown under several effector molecules such as treholose, ectoines, and citrulline in order to discriminate the morphology differences in various conditions. The direct imaging of proteinaceous fibrils with electron beam was possible only in narrow windows of imaging conditions due to the facilitation of electrostatic charging effect, which is dependent on the underlying substrate. The comparisons of images with electron beams and physical tip-contact were conducted and analyzed in terms of measurement speed, charging, and mechanical damages.