Reduction of long-range interactions using carbon nanotube probes in biological systems

Carbon nanotubes (CNT) have been used as tips in non-contact atomic force m icroscopy (NC-AFM) to observe biomolecules including deoxyribonucleic acid (DNA) molecules. Adhesion and electrostatic forces, which affect NC-AFM mea surements even in vacuum condition, can be drastically reduced by using a C NT tip without thermal treatments for samples. Consequently, stable imaging of DNA molecules was performed under the presence of a water layer and var ious surface charges on the substrate. This is highly advantageous for imag ing biomolecules, which are denatured easily by thermal treatment.