From 1D Rods to 3D Networks: A Biohybrid Topological Diversity Investigated by Asymmetrical Flow Field-Flow Fractionation

Abstract

Biohybrid structures formed by noncovalent interaction between avidin as a bridging unit and biotinylated glycodendrimers based on poly(propyleneimine) (GD-B) have potential for biomedical application. Therefore, an exact knowledge about molar mass, dispersity, size, shape, and molecular structure is required. Asymmetrical flow field-flow fractionation (AF4) was applied to separate pure and assembled macromolecules according to their diffusion coefficients. The complex biohybrid structures consist of single components (avidin, differently valent GD-B) and nanostructures. These nanostructures were systematically studied depending on the degree of biotinylation and ligand−receptor stoichiometry by AF4 in combination with dynamic and static light scattering detection. This enables the quantification of composition and calculation of molar masses and radii, which were used to analyze scaling properties and apparent density of the formed structures. These data are compared to hydrodynamic radii obtained by applying the retention theory to the AF4 data. It is shown that depending on their architecture the molecular shape of biohybrid structures is changed from rod-like to spherical toward network-like behavior.

Size Separation Techniques for the Characterisation of Cross-Linked Casein: A Review of Methods and Their Applications

“…For that, MALS, differential refractive index (dRI), UV/Vis, and dynamic light scattering (DLS) are commonly applied [177]. Additional information on similar parameters could be delivered by differential viscometer [178], and structure and molecular composition can be further investigated by coupling AF4 to nuclear magnetic resonance (NMR) [179] and FT-IR [180].…”

“…For homogeneous hard sphere the ratio is equal to 0.775, for linear random coil is between 1 and 2, and for elongated conformations the ratio is up to 2 [200]. The determination of the diffusion coefficient and thus the hydrodynamic radius is also possible from the AF4 elution time (see Section 5.1, Equation (3)); however, both approaches possess advantages and limitations that were treated in depth in the bioconjugation of synthetic macromolecules and proteins [177,[201][202][203][204][205].…”

Shape characterization of polymersome morphologies via light scattering techniques

“…The ratio of the two radii gives a shape ratio, ρ, which is specific to the particle morphology. [21][22][23][24][25][26] The combination of AF4-MALS-QELS was previously used to characterize several morphologies of polymer aggregates, in particular micelles. [27][28][29][30] The use of this technique to characterize the shapes of different polymer vesicles has been overlooked so far.…”

Ligands and characterization for effective bio‐atom‐transfer radical polymerization

“…In addition to GPC analysis, the molar masses of pCBMA and pOEGMA were also determined by AF4‐MALLS. The main advantages of using the channel‐based separation technique of AF4‐MALLS are avoiding interactions with separation columns, very broad separation ranges, as well as gentler separation due to significantly reduced shear forces . Another advantage is that, using MALLS, one can obtain the absolute molar mass of the sample based on the Rayleigh ratio R θ , without the need to use calibration standards .…”