Surface Detail and Inner Granule Structure Revealed by AFM

Surface Detail and Inner Granule Structure Revealed by AFM 

Using suitable preparation techniques, reproducible AFM imaging of starch granules has been performed. While studies performed to date had different aims and resulted in images of the starch granules at different resolutions, they are complementary in nature and demonstrate both the versatility and applicability of the AFM technique to starch research. It is, nevertheless, important to recognize the primary sources of artifacts in AFM images.104,111 

High-Resolution AFM (and LVSEM) Studies of Starch Granule Surface Structure 

10000X, scale bar represents 3 pm) (b) LVSEM micrograph of a typical region of a Riband wheat starch granule surface. (Magnification 10000X, scale bar represents 3pm) 

Another method used for starch is the non-contact mode, where the starch granules are simply spread onto an adhesive tape fixed on the AFM sample holder. Using this technique, both nodules (20-50 nm in diameter) and smooth areas without any visible features were observed at the surface of potato starch granules.114 Multiple freeze-thaw cycles have revealed an internal, lamellar structure of chain clusters bundled into blocklets 50-300 nm in diameter.115 

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