Conformations and diffusion of flexibly linked colloidal chains

Utrecht University Repository (Utrecht University)

Abstract

For biologically relevant macromolecules such as intrinsically disordered proteins, internal degrees of freedom that allow for shape changes have a large influence on both the motion and function of the compound. A detailed understanding of the effect of flexibility is needed in order to explain their behavior. Here, we study a model system of freely-jointed chains of three to six colloidal spheres, using both simulations and experiments. We find that in spite of their short lengths, their conformational statistics are well described by two-dimensional Flory theory, while their average translational and rotational diffusivity follow the Kirkwood–Riseman scaling. Their maximum flexibility does not depend on the length of the chain, but is determined by the near-wall in-plane translational diffusion coefficient of an individual sphere. Furthermore, we uncover shape-dependent effects in the short-time diffusivity of colloidal tetramer chains, as well as non-zero couplings between the different diffusive modes. Our findings may have implications for understanding both the diffusive behavior and the most likely conformations of macromolecular systems in biology and industry, such as proteins, polymers, single-stranded DNA and other chain-like molecules.

Authors 9

1. Ruben W. Verweij Aachen Huygens-Kamerlingh Onnes Laboratory

   Leiden University

   Affiliation as printed

   Huygens-Kamerlingh Onnes Laboratory, Leiden University, Leiden, The Netherlands

2. Pepijn G. Moerman

   Utrecht University

   Affiliation as printed

   Debye Institute for Nanomaterials research, Department of Chemistry, Utrecht University, Utrecht, The Netherlands

   Debye Institute for Nanomaterials research, Department of Physics, Utrecht University, Utrecht, The Netherlands

3. Loes P. P. Huijnen Aachen Huygens-Kamerlingh Onnes Laboratory

   Leiden University

   Affiliation as printed

   Huygens-Kamerlingh Onnes Laboratory, Leiden University, Leiden, The Netherlands

4. Nathalie E. G. Ligthart

   Utrecht University

   Affiliation as printed

   Debye Institute for Nanomaterials research, Department of Chemistry, Utrecht University, Utrecht, The Netherlands

5. Indrani Chakraborty Aachen Huygens-Kamerlingh Onnes Laboratory

   Leiden University · Birla Institute of Technology and Science, Pilani - Goa Campus · Birla Institute of Technology and Science, Pilani

   Affiliation as printed

   Department of Physics, Birla Institute of Technology and Science, Pilani—K K Birla Goa Campus, Zuarinagar, Goa, India

   Huygens-Kamerlingh Onnes Laboratory, Leiden University, Leiden, The Netherlands

6. Jan Groenewold

   South China Normal University · Utrecht University

   Affiliation as printed

   Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, People's Republic of China

   Debye Institute for Nanomaterials research, Department of Chemistry, Utrecht University, Utrecht, The Netherlands

7. Willem K. Kegel

   Utrecht University

   Affiliation as printed

   Debye Institute for Nanomaterials research, Department of Chemistry, Utrecht University, Utrecht, The Netherlands

8. Alfons van Blaaderen

   Utrecht University

   Affiliation as printed

   Debye Institute for Nanomaterials research, Department of Physics, Utrecht University, Utrecht, The Netherlands

9. Daniela J. Kraft corresponding Aachen Huygens-Kamerlingh Onnes Laboratory

   Leiden University

   Affiliation as printed

   Huygens-Kamerlingh Onnes Laboratory, Leiden University, Leiden, The Netherlands