Molecular resolution imaging of polyglucose by scanning tunneling microscopy.

We have obtained atomic resolution images of poly-alpha-D-glucose by scanning tunneling microscopy. The oxygen atoms near the scanning tip were imaged, but the carbon and hydrogen atoms were not visible. The measured inter-atomic distances are consistent with the molecular structure of poly-alpha-D-glucose deduced from chemical and X-ray diffraction studies. The results also demonstrate that is is feasible to image surface atomic structures of a relatively thick non-conducting specimen, suggesting that the technique may be applied to the study of other macromolecules of biological importance.