Synthesis and Characterization of Novel Multivalent Glycogold Nanoparticles as Antibiofilm and Antibacterial Agents

Student thesis: Doc typesDoctor of Sciences

Abstract

Gold nanoparticles have attracted significant interest in many fields due to their
unique physical and chemical properties. Previous studies have shown that the key properties of gold nanoparticles are dependent on their size and morphology. In real biological systems, the interfaces are usually not flat, which exhibit distinct size-features from microns (e.g., cell membranes) or sub-micron (e.g., organelles or vesicles) to several nanometers (e.g., proteins, micelles). Theoretical investigation indicated the size may have great influence on folding of proteins adsorbed on nanoparticles. This dissertation focus on the synthesis and characterization of multivalent glycofullerene gold nanoparticles of various sizes, as well as their applications in inhibition of bacterial growth and formation of biofilm.
A wide range of multivalent disulfide glycofullerenes displaying different
lengths of linker and sugar units (mannose, galactose, fucose) were synthesized via copper(Ⅰ)-catalysed azide-alkyne Huisgen cycloaddition. The biologically active ligands were conjugated to the gold nanoparticles surface by ligand exchange reactions.
Varying sizes of glycofullerene AuNPs, including 20 nm, 60 nm and 100 nm
were prepared by citrate reduction, seeding-growth and surface ligand exchange
methods. The latter methodology could efficiently produce monodispersed large sized glycofullerene AuNPs, that were characterized by XPS, UV, DLS and TEM. With increasing the size, the red-shift of the UV absorption peak of citrate AuNPs was observed. Meanwhile there were constant differences between before and after exchange for the larger size AuNPs.
In order to investigate the impact of the length of spacer linkage and the gold
nanoparticles size on the binding affinity of glycoAuNPs, we used glycofullerene
AuNPs to study interactions with lectins, FimH and DC-SIGN. The results have
showed that the 20 nm glycofullerene AuNPs possess excellent ability of binding to both lectins.4
Importantly, we could show that AuNPs functionalized by glycofullerenes were
better lectins ligands than the corresponding AuNPs bearing monosaccharidic ligands. These results showed that biological properties of glyco-AuNPs can be affected by the size of the nanoparicles as well as by the density of ligands at their surface.
Date of Award28 Oct 2020
Original languageEnglish
Awarding Institution
  • University of Namur
SupervisorStephane VINCENT (Supervisor), Jean-Yves Matroule (President), Carmela APRILE (Jury), Emilie THIERY (Jury) & Mihai Barboiu (Jury)

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