Biological Applications of STM & AFM in Water/High Resolution Microscopy of Nucleoprotein Complexes in Water.

Sample preparation methods and new instrumentation have been developed for the study of biological molecules in their native aqueous environment by scanning tunneling microscopy STM and atomic force microscopy AFM. Information from STM is complicated by the many different electron transfer mechanisms, so structural information is difficult to obtain. However, chemical identification of certain electroactive molecules may be possible at the single molecule level. A new AFM with a magnetically-oscillated tip was used to generate images of DNA of unprecedented resolution. The DNA was imaged in-situ, spontaneously adsorbed to mica in the presence of divalent ions.