Video-Rate Atomic Force Microscopy

M. Kocun, I. Revenko, T. Limpoco, D. Walters, M. Viani, R. Proksch
Asylum Research,
United States

Keywords: AFM

Summary:

We present results from a new, video rate AFM (Cypher VRS) capable of imaging delicate samples in air and fluid up to 625 lines/second (or 10 frames per second). This is about 300x faster than typical AFMs and 10x faster than current “fast scanning” AFMs. The Cypher VRS is the only AFM to achieve these speeds while still offering the versatility and ease of use of a full-featured research AFM. It’s ideal for researching dynamic events such as biochemical reactions, membrane studies, self-assembly, and boundless other applications in materials and life science. We will describe the architecture of this new AFM, and demonstrate the advantages of its unique design. Some recent specific examples are shown, including: (1) real time observation of the cleavage of a DNA molecule with the DNase1 enzyme. (2) a variety of high resolution examples including Bacteriorhodopsin molecules, the DNA double helix and single atomic point defects, all acquired at frame rates in excess of 1 frame per second, (3) the self-assembly of type I Collagen molecule into fibrils. Collagen molecules were injected on a bare mica surface and let spontaneously polymerize to form fibrils in a phosphate buffer.  The typical banding pattern of 67 nm appeared as early as 1 min after introduction of the molecules, and, finally, (4) the dynamics of CTAB hemi-micelles at the solid-liquid interface (HOPG and aqueous buffer). These long molecules spontaneously form micelles in aqueous solutions and hemicylindrical structures upon adsorption onto HOPG. AFM can image these structures with high resolution but with the VRS the kinetics of the formation can now  be followed in real time.