Aug 29, 2019

Model-Free Rheo-AFM Probes the Viscoelasticity of Tunable DNA Soft Colloids

José A Moreno-GuerraMarco Laurati


Atomic force microscopy rheological measurements (Rheo-AFM) of the linear viscoelastic properties of single, charged colloids having a star-like architecture with a hard core and an extended, deformable double-stranded DNA (dsDNA) corona dispersed in aqueous saline solutions are reported. This is achieved by analyzing indentation and relaxation experiments performed on individual colloidal particles by means of a novel model-free Fourier transform method that allows a direct evaluation of the frequency-dependent linear viscoelastic moduli of the system under investigation. The method provides results that are consistent with those obtained via a conventional fitting procedure of the force-relaxation curves based on a modified Maxwell model. The outcomes show a pronounced softening of the dsDNA colloids, which is described by an exponential decay of both the Young's and the storage modulus as a function of the salt concentration within the dispersing medium. The strong softening is related to a critical reduction of the size of the dsDNA corona, down to ≈70% of its size in a salt-free solution. This can be correlated to significant topological changes of the dense star-like polyelectrolyte forming the corona, which are induced b...Continue Reading

  • References34
  • Citations1


  • References34
  • Citations1


  • This paper may not have been cited yet.

Mentioned in this Paper

Steroidogenic acute regulatory protein
Microscopy, Atomic Force

Related Feeds

AFM in situ DNA

AFM in situ DNA describes in situ analysis (or study) of DNA using atomic force microscopy. Discover the latest research on AFM in situ DNA here.