ABSTRACT
Glyconanoparticles (GNPs) are water-soluble carbohydrate-functionalized gold nanoclusters with a promising potential to serve as versatile tools in studies ranging from basic chemical glycobiology to clinical applications. In this paper we evaluate the influence of ligand density and presentation on the recognition by protein receptors by examining the interaction of lactose-functionalized GNPs with two different galactose-specific carbohydrate-binding proteins: an enzyme, Escherichia coli beta-galactosidase, and a lectin, Viscum album agglutinin. The results suggest that the proper selection of ligand densities and spacers in GNP functionalization is an important requisite to match the topological requirements of the target receptor while escaping glycosidase degradation.
Subject(s)
Agglutinins/metabolism , Gold/chemistry , Metal Nanoparticles/chemistry , Plant Lectins/metabolism , beta-Galactosidase/metabolism , Carbohydrate Sequence , Escherichia coli Proteins/metabolism , Models, Theoretical , Molecular Sequence Data , Protein Binding , Viscum album/metabolismABSTRACT
A novel platform for anticancer vaccines has been prepared using glyconanotechnology recently developed in our laboratory. Ten different multifunctional gold glyconanoparticles incorporating sialylTn and Lewis(y) antigens, T-cell helper peptides (TT) and glucose in well defined average proportions and with differing density have been synthesised in one step and characterised using NMR and TEM. Size and nature of the linker were crucial to control kinetics of S-Au bond formation and to achieve the desired ligand ratio on the gold clusters. The technology presented here opens the way for tailoring polyvalent anticancer vaccines candidates and drug delivery carriers with defined average chemical composition.
Subject(s)
Cancer Vaccines/chemical synthesis , Glycoconjugates/chemistry , Metal Nanoparticles/chemistry , Amino Acid Sequence , Animals , Antigens, Tumor-Associated, Carbohydrate/chemistry , Carbohydrate Sequence , Female , Lewis Blood Group Antigens/chemistry , Mice , Microscopy, Electron, Transmission , Molecular Sequence Data , Nanotechnology , Nuclear Magnetic Resonance, Biomolecular , Tetanus Toxoid/chemistryABSTRACT
Thermodynamic evidence for the selective Ca(2+)-mediated self-aggregation via carbohydrate-carbohydrate interactions of gold glyconanoparticles functionalized with the disaccharides lactose (lacto-Au) and maltose (malto-Au), or the biologically relevant trisaccharide Lewis X (Le(X)-Au), was obtained by isothermal titration calorimetry. The aggregation process was also directly visualized by atomic force microscopy. It was shown in the case of the trisaccharide Lewis X that the Ca(2+)-mediated aggregation is a slow process that takes place with a decrease in enthalpy of 160 +/- 30 kcal mol(-)(1), while the heat evolved in the case of lactose and maltose glyconanoparticles was very low and thermal equilibrium was quickly achieved. Measurements in the presence of Mg(2+) and Na(+) cations confirm the selectivity for Ca(2+) of Le(X)-Au glyconanoparticles. The relevance of this result to cell-cell adhesion process mediated by carbohydrate-carbohydrate interactions is discussed.
Subject(s)
Calcium/chemistry , Gold/chemistry , Nanostructures/chemistry , Trisaccharides/chemistry , Animals , Calorimetry/methods , Carbohydrate Sequence , Cations, Divalent/chemistry , Cell Adhesion/physiology , Chick Embryo , Lactose/chemistry , Lewis X Antigen/analogs & derivatives , Magnesium/chemistry , Maltose/chemistry , Microscopy, Atomic Force , Molecular Sequence Data , Neurons/cytology , Oligosaccharides/chemistry , Porifera/cytology , Retina/cytology , ThermodynamicsABSTRACT
Gold glyconanoparticles (GNPs) have been prepared as new multivalent tools that mimic glycosphingolipids on the cell surface. GNPs are highly soluble under physiological conditions, stable against enzymatic degradation and nontoxic. Thereby GNPs open up a novel promising multivalent platform for biological applications. It has recently been demonstrated that specific tumor-associated carbohydrate antigens (glycosphingolipids and glycoproteins) are involved in the initial step of tumor spreading. A mouse melanoma model was selected to test glyconanoparticles as possible inhibitors of experimental lung metastasis. A carbohydrate-carbohydrate interaction is proposed as the first recognition step for this process. Glyconanoparticles presenting lactose (lacto-GNPs) have been used successfully to significantly reduce the progression of experimental metastasis. This result shows for the first time a clear biological effect of lacto-GNPs, demonstrating the potential application of this glyconanotechnology in biological processes.
Subject(s)
Gold/therapeutic use , Lactose/therapeutic use , Nanotechnology/methods , Neoplasm Metastasis/drug therapy , Animals , Cell Adhesion/drug effects , Cell Line, Tumor , Glycosphingolipids , Lung Neoplasms/prevention & control , Lung Neoplasms/secondary , Melanoma, Experimental/drug therapy , Melanoma, Experimental/pathology , Mice , Molecular Mimicry , Neoplasm Invasiveness/prevention & control , Neoplasm Metastasis/prevention & control , Particle Size , Treatment OutcomeABSTRACT
A simple and versatile methodology is described for tailoring sugar-functionalised gold nanoclusters (glyconanoparticles) that have 3D polyvalent carbohydrate display and globular shapes. This methodology allows the preparation of glyconanoparticles with biologically significant oligosaccharides as well as with differing carbohydrate density. Fluorescent glyconanoparticles have been also prepared for labelling cells in biological tests. The materials are water soluble, stable under physiological conditions and present an exceptional small core size. All of them have been characterised by (1)H NMR, UV and IR spectroscopy, TEM and elemental analysis. Their highly polyvalent network can mimic glycosphingolipid clustering and interactions at the plasma membrane, providing an controlled system for glycobiological studies. Furthermore, they are useful building blocks for the design of nanomaterials.
Subject(s)
Carbohydrates/chemistry , Glycocalyx/chemistry , Gold/chemistry , Microspheres , Carbohydrate Sequence , Chromatography, Thin Layer , Fluorescein-5-isothiocyanate , Fluorescent Dyes , Indicators and Reagents , Ligands , Molecular Mimicry , Molecular Sequence Data , Surface PropertiesABSTRACT
Glycosphingolipid clustering and interactions at the cell membrane can be modeled by gold glyconanoparticles prepared with biologically significant oligosaccharides. Such water-soluble gold glyconanoparticles with highly polyvalent carbohydrate displays (see picture, gray hemisphere: gold nanoparticle) have been obtained by a simple and versatile strategy.
