Improved DNA straightening and attachment via optimal Mg2+ ionic bonding under electric field for AFM imaging in liquid phase. (September 2019) - Liu, Ziyu
Highlights: Proposed a new method to improve DNA straightening under an applied electric field. The straightened DNA could be successfully imaged and manipulated in liquid media by quantitative AFM imaging. Mg 2+ ion-modified mica substrate enabled DNA straightening under DC electric field. The new technique is of great significance for the biomedicine field. Abstract: In this research, a novel method is proposed to improve DNA straightening under an applied electric field to facilitate imaging in a liquid phase by modifying the substrate with varying Mg 2+ ion concentrations. A two-dimensional network of DNA structures was successfully stretched on Mg 2+ -modified mica substrates under a DC electric field (1 V, 1 A) and imaged in gaseous and aqueous phases by atomic force microscopy. The results revealed that an optimum concentration of Mg 2+ ion (4.17 μmol/ml) allowed DNA straightening under an electric field, thus facilitating its imaging in the liquid phase. Furthermore, DNA adhesion under different concentrations of Mg 2+ was measured and a maximum adhesion force of 76.19 pN was achieved. This vital work has great potential in gene knockout and targeted gene editing.