Sphere-Like Protein–Glycopolymer Nanostructures Tailored by Polyassociation

Key parameters allow a reproducible polyassociation between avidin and biotinylated glycopolymers in order to fabricate defined supramolecular nanostructures for future (bio)­medical and biotechnological applications. Thus, the polymerization efficiency of biotinylated glycopolymers in the fabrication of biohybrid structures (BHS) was investigated with regard to the influence of (i) the degree of biotinylation of the dendritic glycoarchitectures, (ii) two biotin linkers, (iii) the dendritic scaffold (perfectly branched vs hyperbranched), and (iv) the ligand–receptor stoichiometry. The adjustment of all these parameters opens the way to fabricate defined sizes of the final biohybrid structures as a multifunctional platform ready for their use in different applications. Various analytical techniques, including purification of BHS, were used to gain fundamental insights into the structural properties of the resulting protein–glycopolymer BHS. Finally, the elucidation of pivotal conformational properties of isolated BHS with defined sizes by asymmetrical flow field flow fractionation study revealed that they mainly possess spherical-/star-like properties. From this study, the fundamental knowledge can be likely transferred to other assemblies formed by molecular recognition processes (e.g., adamantane-β-cyclodextrin)

Coil-like Enzymatic Biohybrid Structures Fabricated by Rational Design: Controlling Size and Enzyme Activity over Sequential Nanoparticle Bioconjugation and Filtration Steps

Well-defined enzymatic biohybrid structures (BHS) composed of avidin, biotinylated poly­(propyleneimine) glycodendrimers, and biotinylated horseradish peroxidase were fabricated by a sequential polyassociation reaction to adopt directed enzyme prodrug therapy to protein–glycopolymer BHS for potential biomedical applications. To tailor and gain fundamental insight into pivotal properties such as size and molar mass of these BHS, the dependence on the fabrication sequence was probed and thoroughly investigated by several complementary methods (e.g., UV/vis, DLS, cryoTEM, AF4-LS). Subsequent purification by hollow fiber filtration allowed us to obtain highly pure and well-defined BHS. Overall, by rational design and control of preparation parameters, e.g., fabrication sequence, ligand–receptor stoichiometry, and degree of biotinylation, well-defined BHS with stable and even strongly enhanced enzymatic activities can be achieved. Open coil-like structures of BHS with few branches are available by the sequential bioconjugation approach between synthetic and biological macromolecules possessing similar size dimensions