Imaging Crystals, Polymers, and Processes in Water with the Atomic Force Microscope

TLDR

AFM can image the surfaces of both conductors and nonconductors even when covered with water or aqueous solutions. The system used micro‑fabricated cantilevers coupled to an optical lever to monitor cantilever deflection. Atomic‑resolution images of mica, polyalanine, and real‑time fibrin polymerization demonstrate AFM’s ability to reveal corrosion, biomolecular structure, and dynamic biological processes at the atomic scale.

Abstract

The atomic force microscope (AFM) can be used to image the surface of both conductors and nonconductors even if they are covered with water or aqueous solutions. An AFM was used that combines microfabricated cantilevers with a previously described optical lever system to monitor deflection. Images of mica demonstrate that atomic resolution is possible on rigid materials, thus opening the possibility of atomic-scale corrosion experiments on nonconductors. Images of polyalanine, an amino acid polymer, show the potential of the AFM for revealing the structure of molecules important in biology and medicine. Finally, a series of ten images of the polymerization of fibrin, the basic component of blood clots, illustrate the potential of the AFM for revealing subtle details of biological processes as they occur in real time.