Adsorption processes at single molecule level are of fundamental importance for the understanding and development of biomaterials. Atomic force microscopy (AFM) has played a critical role in this field due to its high resolution and ability to image in a liquid environment. We present a method that improves the dynamic force sensitivity and the resolution of a conventional AFM. This is achieved via a positive feedback loop that enhances the effective quality factor of the cantilever in a liquid environment to values in excess of 300, compared to a nominal value of similar to1. This active quality factor enhancement has been used to image DNA and an increase in the height of the molecule observed. (C) 2001 Elsevier Science B.V. All rights reserved.
- PLASMID DNA
- ATOMIC-FORCE MICROSCOPY
- atomic force microscopy
- biological molecules - nucleic acids
- surface structure