Extending and manipulating long DNA molecules for high resolution analysis-development of a novel nanobiotechnological tool for atomic force microscopy

Many methods were developed to image DNA by AFM both in ambient conditions and under physiological ones. The main difficulty in physically mapping DNA molecules is that they exist as random coils. Such conformation makes it difficult or impossible to obtain quantitative structural information especially when a DNA fragment longer than several thousands bases is used. Using a very low concentration of silane to introduce limited number of amino groups to the surface was a key point in fine tuning the crosslinking reaction without strongly adsorbing DNA to the surface. Such treatment allowed stretching the tethered molecules in one direction.