Reversible and Irreversible Mechanical Damaging of Large Double-Stranded DNA upon Electrospraying

• Published in: Analytical chemistry (Washington) Vol. 88; no. 14; pp. 7295 - 7301
• Main Authors: Shlyapnikov, Yuri M, Shlyapnikova, Elena A, Morozov, Victor N
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 19-07-2016
• Subjects: Bacteriophage lambda - genetics; Cobalt - chemistry; Condensation; Damage; Deoxyribonucleic acid; DNA - analysis; DNA - chemistry; DNA Damage; Electrohydrodynamics; Electrophoresis, Agar Gel; Fragmentation; Fragments; Ions; Ions - chemistry; Mass spectrometry; Mechanical Phenomena; Microscopy, Atomic Force; Shear stress; Viscous drag
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/acs.analchem.6b01642

Electrohydrodynamic spraying (or electrospaying, ES) of DNA solutions is an attractive technique for applications in mass spectrometry, in microarray fabrication, and in generation of DNA nanoaerosols. Here we report how ES affects DNA structure and evaluate possible ways to reduce DNA damage upon ES. It is shown that under any ES conditions, linear λ-phage DNA is subjected to intensive rupture producing a mixture of fragments. In addition to such fragmentation, notable reversible changes in the DNA structure were revealed by a slight increase in DNA electrophoretic mobility. The degree of fragmentation was shown to decrease with decreased DNA length and with increased flow rate through the ES capillary. Fragments shorter than 5 kbp did not show any notable damage upon ES. Both experimental data and theoretical estimations of the forces acting on DNA during ES indicate that DNA is damaged by mechanical forces, and the damage takes place in the vicinity of the Taylor cone tip, presumably due to the high shear stress or/and viscous drag forces operating there. Condensation of λ-DNA with hexamminecobalt­(III) ions completely protected it from any damage upon ES.