Synthesis of Gold Glyconanoparticles and Biological Evaluation of Recombinant Gp120 Interactions

Abstract

As part of our continuing efforts to study the molecular events involved in HIV recognition of mucosal membrane cells, we are studying the interactions of the HIV-associated glycoprotein gp120, with the cellular receptor GalCer. In this work, we report investigations of multivalent interactions of Au glyconanoparticles containing galactosyl and glucosyl headgroups with recombinant gp120. These particles were prepared from disulfides containing C-glycosides linked to triethylene glycol via an amide bond using a modification of the Brust method. 1 Results from transmission electron microscopy, atomic force microscopy, and UV-vis absorption spectroscopy data are consistent with an average particle diameter of 2 nm. Elemental analyses indicate that the average composition of the particles is 1.6:1 Au:carbohydrate. A biotin-NeutrAvidin adhesion assay was used to evaluate the relative ability of carbohydrate disulfides and Au glyconanopraticles to displace rgp120 from plate-bound GalCer. The data indicate that divalent disulfides were less than 12% as active as biotinylated GalCer, a water-soluble surrogate of GalCer. However, when these same carbohydrates were presented in a polyvalent display on gold, they were greater than 300 times more active than the disulfides and at least 20 times more active than biotinylated GalCer. These results collectively demonstrate the potential utility of polyvalent ligand arrays on nanoplatforms.

Globotriose‐Functionalized Gold Nanoparticles as Multivalent Probes for Shiga‐like Toxin

“…This strategy allowed us to modify the surface carbohydrate ligand density by ligand-exchange processes. [42] Although gas chromatography (GC) [43] and elemental analysis (EA) [26,28] are suitable methods for determining the amount of conjugated carbohydrate on AuNPs, the sample amount that is required is about ten-fold higher than that needed for the equivalent analysis by a chemical colorimetric method. [44] With the latter method, in general, carbohydrates are reacted with phenol in the presence of sulfuric acid to give heterocyclic compounds, which are then quantified by UV spectroscopy.…”

“…These gold glyconanoparticles have been used successfully as carriers to present carbohydrate ligands for studying carbohydrate-protein and carbohydrate-carbohydrate interactions. [27][28][29][30][31][32] Previously, we demonstrated the labeling of a specific protein on the bacterial cell surface by using mannose-conjugated AuNPs (m-AuNP). [33] m-AuNPs were used to visualize the position of individual FimH proteins on the type 1 pilus of E. coli by using electron microscopy.…”

Integrated Nanoparticle–Biomolecule Hybrid Systems: Synthesis, Properties, and Applications

“…[83] These particles were prepared from disulfides, which contained C-glycosides linked to triethylene glycol through an amide bond, by using a modification of the Brust method.…”

Synthesis of 28-membered macrocyclic polyammonium cations functionalized gold nanoparticles and their potential for sensing nucleotides

“…A catalytic function of Au-NPs for the oxidation of NADH to NAD + has also been investigated [7]. In addition, the surface plasmon resonance of Au-NPs makes them desirable agents as bio-sensors to detect biomolecules such as DNA, antigen-antibody complexes, and some proteins [8][9][10][11], and as optical sensors to detect anions, cations, and heavy metals [12][13][14][15].…”