Alzheimer's disease is in part characterised by the deposit of beta-amyloid peptide in the form of fibrils in the brain. In this study, the scanning tunnelling microscope (STM) has been used to provide high resolution images of synthetic fibril structure and formation as a function of time. Short fibrils are observed following brief peptide incubation times. At longer incubation periods ribbon like filaments were observed. These results suggest that beta-amyloid self-assembly is an ordered process, with a correlation between time of incubation and length of beta-amyloid filament growth.

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Scanning tunnelling microscopy has been employed to visualize the structure of pig gastric mucin. Typically the expected protein backbone with a carbohydrate brush was observed, but with unexpectedly long carbohydrate chains (100 sugars as compared to 20). A small percentage of the mucin molecules displayed smooth heavily glycosylated regions, joined by naked protein backbone. These structures are consistent with the linear model for mucin sub-unit structure and the swollen random coil and linear random coil models for tertiary organization.

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