Products
HRIM™
VideoAFM™
ActivResonance Controller
- Introduction
- Benefits
- How It Works
- Specifications
- FAQs
For more information about our products, please contact us
ActivResonance Controller - Benefits
How will it benefit my AFM imaging capability?
Our tests have shown considerable imaging improvement when tried on a number of different systems. In each case, we have optimised the imaging conditions as far as possible without ActivResonance Control, before turning on the ActivResonance Control to improve the imaging further.
Here are a few examples:
Gel
Gel samples are particularly difficult to image when swollen. To prevent the surface from drying out they need to be imaged under the swelling solvent. Due to their extreme softness they can easily be deformed even when imaging in dynamic mode.
In the following example a 30% isotactic polystyrene gel in dekalin has been imaged under dekalin with the quality factor of the cantilever enhanced by the ActivResonance Controller. The same area is then imaged without the ActivResonance Controller. From the comparison it is clear that the increase in the quality factor of the cantilever produces much better resolution in the image.
Image on the left, taken with an effective quality factor of 70, shows much finer details than the corresponding image using conventional dynamic mode on the right. The image on the right was fully optimised to enable a fair comparison (scale bar 1 micron).
Images courtesy of Jamie Hobbs and Andy Humphris, University of Bristol
DNA
DNA is an extremely popular specimen for imaging by AFM. Operating in dynamic mode in fluid is often the best technique for studying biomolecules as it minimises lateral forces on the specimen.
The image on the left shows a typical image of entangled DNA molecules deposited on a mica surface. The image was taken using dynamic mode of operation in butanol, and is displayed with a colour table z-range of 3 nm. (Image size is 3 microns x 3 microns.)
By switching on the ActivResonance Controller and imaging the same area, the image on the right was obtained. Shown using exactly the same colour table and z-range, the DNA molecules (and the smaller contamination features) are lighter in colour, and therefore higher. Imaging using the ActivResonance Controller requires operation with far less force exterted on the sample - ideal for delicate or weakly adsorbed biological molecules such as DNA.
Images courtesy of Andy Round, University of Bristol
Cells
Cells are considered to be very difficult to image by AFM - they are large, soft and difficult to keep alive. Using the ActivResonance Controller, the imaging force can be made as low as possible, enabling high quality imaging and helping to keep the cells happy!
The left image is an AFM topographic image of a living rat kidney cell, taken with an effective quality factor of 300. Image is 32 x 32 microns, with a z-range of 2.5 microns.
Right hand image is a simultaneous phase image, z-range 60 degrees.
Images courtesy of Rachel Owen, University of Bristol
SNOM
The quality factor controls the settle time of the probe, and therefore how long the probe takes to react to a change in interaction, for instance when moving over the surface. Thus a high quality factor gives improved force sensitivity but reduced scan speeds.
If the quality factor is very high it can be reduced, allowing faster scans, without having an adverse impact on force sensitivity. In SNOM, or NSOM, where shear-force feedback is used, this is a common problem, especially as scanning too fast, without good height c