Rheological study of a DNA transient network by optophoresis

Micro-rheology recently emerged as a promising technique for investigating the viscoelastic properties of complex fluids at a molecular scale. The study of the rheological properties of polymer solutions and reversible gels is more complex than that of molecular fluids, because these fluids commonly exhibit nonlinear viscosity behaviour. The research activity that we report about has been dedicated to the analysis of the dynamic behaviour of a DNA-particles system. DNA particles shaped as nano-stars with sticky ending points are suspended in water, and by lowering the temperature, below a gelation threshold, the nano-stars stick one to each other to form an hydrogel [1, 2].