Biological materials investigation by atomic force microscope (AFM).

摘要

The Atomic Force Microscope (AFM) has the potential to image biological systems in their native state with molecular resolution. The limitations to the practical application of the AFM in studying biological systems are sample preparation and the adhesion of biological macromolecules to the scanning tip. The biomolecule must be attached to the substrate surface to avoid movement caused by the lateral forces generated during scanning else the drift experienced by the biomolecule limits image resolution or precludes imaging altogether. We have analyzed and compared two sample preparation techniques that ensure reliable deposition of Deoxyribose Nucleic Acid (DNA) onto mica that is used as a substrate. DNA is an attractive candidate for study because of its exquisite specificity in base pairing and ∼1 nm radius. The effects of pressure and time on DNA samples, mechanical nano-manipulation of DNA and the action of restriction enzymes on surface-bound DNA have been analyzed experimentally.