Viscosity Measurements of DNA Solutions with and without Condensing Agents
Arno D. Laesecke, Jessica L. Burger
Aqueous DNA solutions at three concentrations were studied as model sputum by viscosity measurements at ambient pressure. Initial measurements at 25 °C, 37.78 °C, and 50 °C indicated a viscosity increase toward 50 °C. This phenomenon was studied by extended measurements from 10 °C to 90 °C, which revealed concentration-dependent viscosity maxima in the range of 50 °C to 65 °C. The associated viscosity increase were up to 400%. A two-liquids model for solutions of double-and single-stranded DNA is developed that represents the experimental data closely. Three polycations were tested as viscosity-reducing agents with measurements from 25 °C to 50 °C. The most significant viscosity reduction was achieved with spermine in a solution with mg/ml DNA concentration.