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

Area of Science:

• Biophysics
• Materials Science
• Molecular Biology

Background:

• Electrohydrodynamic spraying (ES) is a valuable technique for DNA applications, including mass spectrometry and microarray fabrication.
• Understanding the impact of ES on DNA structure is crucial for optimizing these applications and minimizing DNA damage.

Purpose of the Study:

• To investigate how electrohydrodynamic spraying affects the structural integrity of DNA.
• To identify methods for reducing DNA damage during the electrospaying process.

Main Methods:

• Linear lambda-phage DNA solutions were subjected to electrohydrodynamic spraying under various conditions.
• DNA fragmentation was analyzed using gel electrophoresis to assess structural changes and fragment sizes.
• Theoretical estimations of forces acting on DNA near the Taylor cone tip were performed.

Main Results:

• Electrohydrodynamic spraying consistently caused significant fragmentation of linear lambda-phage DNA.
• Reversible structural changes, indicated by increased electrophoretic mobility, were observed.
• Fragmentation decreased with shorter DNA lengths and increased flow rates; fragments <5 kbp showed no significant damage.
• Mechanical forces, likely shear stress and viscous drag near the Taylor cone, were identified as the cause of DNA damage.
• Condensation of DNA with hexamminecobalt(III) ions completely prevented ES-induced DNA damage.

Conclusions:

• Electrohydrodynamic spraying induces mechanical damage to DNA, primarily through fragmentation.
• DNA length and ES flow rate influence the degree of fragmentation.
• Hexamminecobalt(III) ion condensation offers a highly effective method for protecting DNA from damage during electrohydrodynamic spraying.