We have studied the impact of particle shape anisotropy, multivalent interactions and flexibility on systems of micron-sized colloidal particles. In short, we have characterized the diffusive... Show moreWe have studied the impact of particle shape anisotropy, multivalent interactions and flexibility on systems of micron-sized colloidal particles. In short, we have characterized the diffusive properties of anisotropic dumbbell particles near surfaces. Furthermore, by using experiments and simulations, we have uncovered marked flexibility-induces effects in the Brownian motion of reconfigurable colloidal structures. Our work demonstrates the rich dynamics and possibilities for applications of shape-changing colloidal systems. We hope our findings further the study of the diffusivity of flexible objects found in complex mixtures relevant in, for example, the cosmetic, pharmaceutical and food industries, as well as in biological and drug-delivery systems. For example, our results may have implications for understanding both the diffusive behavior and the most likely conformations of macromolecular systems such as polymers, single-stranded DNA and other chain-like molecules. Show less
The use of colloid supported lipid bilayers (CSLBs) has recently been extended to create colloidal joints, that enable the assembly of structures with internal degrees of flexibility, and to study... Show moreThe use of colloid supported lipid bilayers (CSLBs) has recently been extended to create colloidal joints, that enable the assembly of structures with internal degrees of flexibility, and to study lipid membranes on curved and closed geometries. These novel applications of CSLBs rely on previously unappreciated properties: the simultaneous fluidity of the bilayer, lateral mobility of inserted (linker) molecules and colloidal stability. Here we characterize every step in the manufacturing of CSLBs in view of these requirements using confocal microscopy and fluorescence recovery after photobleaching (FRAP). Specifically, we have studied the influence of different particle properties (roughness, surface charge, chemical composition, polymer coating) on the quality and mobility of the supported bilayer. We find that the insertion of lipopolymers in the bilayer can affect its homogeneity and fluidity. We improve the colloidal stability by inserting lipopolymers or double-stranded inert DNA into the bilayer. We include surface-mobile DNA linkers and use FRAP to characterize their lateral mobility both in their freely diffusive and bonded state. Finally, we demonstrate the self-assembly of flexibly linked structures from the CSLBs modified with surface-mobile DNA linkers. Our work offers a collection of experimental tools for working with CSLBs in applications ranging from controlled bottom-up self-assembly to model membrane studies. Show less
Wel, C.M. van der; Stolpe, G.L. van der; Verweij, R.W.; Kraft, D.J. 2018
