Carbohydrate-Functionalized Nanomaterials Synthesis, Characterization and Biorecognition Studies

Abstract: This thesis focuses on the development of carbohydrate coupling chemistry on nanomaterials and their biological activity studies. It is divided into two parts:In part one, two carbohydrate immobilization approaches, based on perfluorophenyl azide (PFPA)-functionalized silica nanoparticles (SNPs), are presented, where the binding affinity of the glyconanoparticles was evaluated through carbohydrate-lectin interaction. In the first approach, PFPAfunctionalized SNPs were treated with propargylated glycosides and functionalized under copper-catalyzed azide-alkyne cycloaddition (CuAAC) conditions to give glyconanoparticles. For the second approach, a metal-free coupling chemistry based on perfluorophenyl azide-aldehyde-amine cycloaddition (AAAC) was developed for carbohydrate immobilization on PFPA-functionalized SNPs using glycosyl amine and phenylacetaldehyde. Subsequently, a quantitative fluorine nuclear magnetic resonance (19F qNMR) technique was developed to determine the carbohydrate density on the glyconanoparticles. The addition of an internal standard allowed the accurate determination of carbohydrate density, which was then used to calculate the apparent dissociation constant (Kd ) of the glyconanoparticles with lectin by a ligand competition assay. The developed approaches proved general and versatile, and the carbohydrate-presenting nanoplatforms showed high binding specificity in lectin binding.In part two, microwave irradiation was used to functionalize carbon nanomaterials with PFPA followed by carbohydrate conjugation. The microwave-assisted method proved efficient for a number of carbon nanomaterials including carbon nanotubes (CNTs), graphene and fullerene. The carbohydrates on the glyconanomaterials retained their binding patterns towards cognate lectins.