Spin-Stretching of DNA and Protein Molecules for Detection by Fluorescence and Atomic Force Microscopy

We have developed a rapid and efficient way of stretching DNA and denatured protein molecules for detection by fluorescence microscopy and atomic force microscopy (AFM). In the described method, a viscous drag created by transient rotational flow stretches randomly coiled DNA molecules or denatured proteins. Stretching is achieved by dispensing a droplet of sample solution containing DNA or denatured protein on a MgCl2-soaked mica surface. We present fluorescent images of straightened lambdaDNA molecules and AFM images of stress-shared, reduced von Willebrand factor as well as straightened lambdaDNA. The described quick and reliable spin-stretching technique will find wide applications in the analysis of single biopolymer molecules.