Viscoelasticity and Its Influence on the Manipulation of <scp>DNA</scp> Molecules

The viscoelasticity of DNA molecules in the air were investigated using atomic force microscopy (AFM). For the individual DNA, compared to the randomly-coiled DNA, the stretched DNA showed smaller viscoelasticity, measured in the AFM quantitative imaging (QI) mode. The manipulation of DNA was performed, and it was influenced by its viscoelasticity. Compared to the stretched DNA, significant highlighted accumulations of DNA and lateral dragging tails were more obvious for the randomly-coiled DNA, which was caused by the elastic recoil and adhesion effects. In addition, the viscoelasticity of DNA aggregates composed of multiple DNA strands were measured. Compared to the individual DNA, they showed larger viscoelasticity. This study serves as a reference for the studies of DNA viscoelasticity-related behaviors in the air and has potential in gene knockout and targeted gene editing.