The Cypher VRS AFM is the first and only full-featured video-rate AFM. Instead of capturing just AFM images, the Cypher VRS captures AFM movies. Finally, researchers can measure nanoscale dynamic processes from these AFM videos with all of the resolution, versatility, and ease of use that are the hallmarks of an Asylum Research Cypher AFM.
Collagen is the most abundant protein found in humans and other animals. It assembles in vivo into hierarchical structures found in numerous tissues. In addition, it is widely used to create substrates and 3D scaffolds in vitro for cell and tissue culture. Hence, understanding the mechanism of collagen self-assembly has both fundamental and practical importance.
The results shown here were obtained on a Cypher VRS video-rate AFM. Briefly, the movie begins with images of bare mica in buffer obtained in tapping mode at a line rate of 400 Hz with 512×256 pixels for a frame rate of 1.5 frames/second (fps). The movie here is played back at 15 fps, i.e. 10× the acquisition rate. A dilute solution of collagen molecules is added. The three steps of assembly are captured:
Samples provided courtesy of Jinhui Tao and Jim De Yoreo, Pacific Northwest National Laboratory.What could you do with a Cypher VRS?
DNase1 is an enzyme that nonspecifically cleaves DNA. Here, the Cypher VRS was used to monitor the action of DNase1 on lambda digest DNA. Briefly, the DNA was bound to a mica substrate with MgCl2 buffer, and DNase was introduced. Images were obtained in tapping mode at a line rate of 625 Hz with 320×64 pixels using an Olympus AC10 probe for a frame rate of 8.7 frames per second (fps). Beside the movie, we’ve selected three key frames taken over an interval of just 2.5 seconds. In the first image (top), several DNA strands are observed. In the second image (center), note the DNase enzyme bound to one of the overlapping strands (circle). In the third and last image (bottom), this strand has been cleaved at the binding point.Talk to an AFM Expert
In this experiment we captured the dynamics of hemicylindrical micelles, formed in a 2 mM CTAB solution, migrating across the surface of HOPG. The micelles are normally quite stable so we perfused in a small amount of isopropyl alcohol to induce dynamics. For these movies we acquired images (200×200 pixels) at 2.4 frames per second. In order to visualize the dynamics more clearly the playback rate is 6× faster than the acquisition rate.Ask for more information
A lambda digest DNA sample was prepared for AFM imaging using a typical preparation where the DNA solution (1 μg/µL λDNA in 10 mM NiCl₂) is allowed to adsorb to a freshly cleaved mica disc. The sample was loaded in the Cypher VRS and prepared for imaging. Then a 100 mM potassium hydroxide solution was introduced, which was expected to denature the DNA (i.e. unravel the DNA double-helix, forming single stranded DNA). Video-rate AFM imaging immediately commenced using an Asylum Research Cypher VRS atomic force microscope, scanning at 625 lines per second with an Olympus AC10 probe at a scan size of 160 nm with 448 points per line and 52 lines, for an effective frame rate of 9.19 frames/second. The video plays back here in real-time (i.e. 1× the acquisition rate).
Initial image frames show the expected intact DNA structure, but finer strands corresponding to single-strand DNA quickly appear, oftentimes appearing to remain connected to the original DNA strand.
Imaged on an Asylum Research Cypher VRS atomic force microscope at 100 Hz with 312×64 pixels using an Olympus AC10 probe for a frame rate of 1.56 fps; playback: 10× acquisition rate (15.6 fps)