Rod-Like Virus-Based Multiarm Colloidal Molecules

Abstract

We report on the construction of multiarm colloidal molecules by tip-linking filamentous bacteriophages, functionalized either by biological engineering or chemical conjugation. The affinity for streptavidin of a genetically modified vector phage displaying Strep-tags fused to one end of the viral particle is measured by determining the dissociation constant, K. In order to improve both the colloidal stability and the efficiency of the self-assembly process, a biotinylation protocol having a chemical yield higher than 90% is presented to regioselectively functionalize the cystein residues located at one end of the bacteriophages. For both viral systems, a theoretical comparison is performed by developing a quantitative model of the self-assembly and interaction of the modified viruses with streptavidin compounds, which accurately accounts for our experimental results. Multiarm colloidal structures of different valencies are then produced by conjugation of these tip-functionalized viruses with streptavidin activated nanoparticles. We succeed to form stable virus-based colloidal molecules, whose number of arms, called valency, is solely controlled by tuning the molar excess. Thanks to a fluorescent labeling of the viral arms, the dynamics of such systems is also presented in real time by fluorescence microscopy.

Sphere–Tubule Superstructures through Supramolecular and Supracolloidal Assembly Pathways

“…The latter can be achieved through different pathways taking advantage of anisotropic shapes to locally adsorb or edge molecules at the surface of the particles . Other studies rely either on local chemical modifications, as seen for instance in the case of viruses, or functionalization, the most prominent example being the association of DNA functionalized colloidal molecules into defined lattices . Framed in this nonexhaustive review, it is worth noting that supracolloidal assemblies can as well be triggered by application of external force fields, which in combination with the shape of the particles can result in spectacular assemblies .…”

“…Framed in this nonexhaustive review, it is worth noting that supracolloidal assemblies can as well be triggered by application of external force fields, which in combination with the shape of the particles can result in spectacular assemblies . Complex colloidal organizations have been reported through the multicomponent association of isotropic and anisotropic building blocks . One of the rationales behind this multicomponent approach is the design of units with tunable valence that could further flexibly build well‐defined hierarchical assemblies .…”

Directing Liquid Crystalline Self-Organization of Rodlike Particles through Tunable Attractive Single Tips

“…The particles are semi-flexible with a persistence length of L p 3L [23]. The presence of cysteine residues only at one of the ends allows, after chemical reduction, for their selective bioconjugation with maleimide activated fluorescent compounds (Dylight 550 and 594 Maleimide, ThermoFisher), as described elsewhere [24,25].…”

Elementary Edge and Screw Dislocations Visualized at the Lattice Periodicity Level in the Smectic Phase of Colloidal Rods

“…This results in 1.0 µm long tiplabeled viral particles, called M 13 redT ip , whose phase behavior in aqueous suspension presents liquid crystalline ordering, as the lamellar organization including smectic-A and smectic-B phases in the dense regime [28,29]. Part of these tip-functionalized viruses were body-labeled with green fluorescent dyes (Alexa488-NHS ester activated, Molecular Probes) [27] and added in tracer amounts to a few M 13 redT ip samples for single particle tracking experiments. A set of samples with concentrations in the smectic-A range were prepared (in 17mM BisTris-HCl-NaCl buffer, pH 7, with 3 mM NaN 3 as bactericide, for a total ionic strength of 20 mM) between cover slip and glass slides, and observations were performed using an optical microscope (IX-71 Olympus), equipped with a high-numerical aperture (NA) oil objective (100X PlanApo NA 1.40), a piezo device for objective vertical positioning (P-721 PIFOC Piezo Flexure Objective Scanner, PI), a fluorescence excitation light source (Xcite series 120 Q) and an ultra-fast electron-multiplying camera (NEO sCMOS Andor) with a pixel size of 6.5 µm.…”