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Just like atoms combine into molecules, colloids can self-organize into predetermined structures according to a set of design principles. Controlling valence—the number of interparticle bonds—is a prerequisite for the assembly of complex architectures. The assembly can be directed via solid “patchy” particles with prescribed geometries to make, for example, a colloidal diamond. We demonstrate here that the nanoscale ordering of individual molecular linkers can combine to program the structure of microscale assemblies. Specifically, we experimentally show that covering initially isotropic microdroplets withNmobile DNA linkers results in spontaneous and reversible self-organization of the DNA intoZ(N) binding patches, selecting a predictable valence. We understand this valence thermodynamically, deriving a free energy functional for droplet–droplet adhesion that accurately predicts the equilibrium size of and molecular organization within patches, as well as the observed valence transitions withN. Thus, microscopic self-organization can be programmed by choosing the molecular properties and concentration of binders. These results are widely applicable to the assembly of any particle with mobile linkers, such as functionalized liposomes or protein interactions in cell–cell adhesion.
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A Laboratory Model for Virus Particle Nanoindentation
ABSTRACT Self-organization is ubiquitous in biology, with viruses providing an excellent illustration of bioassemblies being much more than the sum of their parts. Following nature's lead, molecular self-assembly has emerged as a new synthetic strategy in the past 3 decades or so. Self-assembly approaches promise to generate complex supramolecular architectures having molecular weights of 0.5 to 100 MDa and collective properties determined by the interplay between structural organization and composition. However, biophysical methods specific to mesoscopic self-assembly, and presentations of the challenges they aim to overcome, remain underrepresented in the educational laboratory curriculum. We present here a simple but effective model for laboratory instruction that introduces students to the world of intermolecular forces and virus assembly, and to a cutting-edge technology, atomic force microscopy nanoindentation, which is able to measure the mechanical properties of single virus shells in vitro. In addition, the model illustrates the important idea that, at nanoscale, phenomena often have an inherent interdisciplinary character.
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- PAR ID:
- 10201969
- Date Published:
- Journal Name:
- The Biophysicist
- Volume:
- 1
- Issue:
- 2
- ISSN:
- 2578-6970
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.35459/tbp.2019.000106
