New Insights from Sum Frequency Generation Vibrational Spectroscopy into the Interactions of Islet Amyloid Polypeptides with Lipid Membranes

Figure 6

Bonn and coworkers compared the inhibitory effect of EGCG on hIAPP fibrillation in the bulk and at the phospholipid interface. (a) In the bulk, the formation of hIAPP amyloid fibrils was measured using a ThT fluorescence assay. The sigmoidal increase in fluorescence signal in the absence of EGCG (×) indicates the formation of hIAPP fibrils, and the low fluorescence signal in the presence of EGCG at a 1 : 1 molar ratio (+) suggests the inhibition of fibril formation. At the phospholipid interface, in absence () and presence (□) of EGCG, SFG spectra measure the formation of β-sheets. (b) AFM also shows hIAPP fibrils formed in the absence of EGCG and (c) EGCG completely inhibits fibril formation of hIAPP. Adapted from [64] with permission. Copyright 2012 American Chemical Society.