Quantitative Fluorine NMR To Determine Carbohydrate Density on Glyconanomaterials Synthesized from Perfluorophenyl Azide-Functionalized Silica Nanoparticles by Click Reaction

Abstract

A quantitative fluorine NMR ((19)F qNMR) method was developed to determine the carbohydrate density on glyconanomaterials. Mannose (Man)- and galactose (Gal)-conjugated silica nanoparticles (SNPs) were synthesized from perfluorophenyl azide (PFPA)-functionalized SNPs and propargylated Man or Gal by copper-catalyzed azide-alkyne cycloaddition (click reaction). After treating PFPA-SNPs or Man-SNPs with hydrofluoric acid followed by lyophilization, the remaining residues were directly subjected to (19)F NMR analysis. The density of PFPA on PFPA-SNP was determined to be 7.7 ± 0.2 × 10(-16) nmol/nm(2) and Man on Man-SNP to be 6.4 ± 0.2 × 10(-16) nmol/nm(2) giving a yield of ∼83% for the click coupling reaction. The apparent dissociation constant (Kd) of Man-SNPs with fluorescein isothiocyanate (FITC)-concanavalin A (Con A) was determined using a fluorescence competition assay to be 0.289 ± 0.003 μM, which represents more than 3 orders of magnitude affinity increase compared to free Man with Con A.

A versatile catalyst-free perfluoroaryl azide–aldehyde–amine conjugation reaction

“…1e), corresponding to an immobilized ligand density of (13.4 ± 2.5) × 10 −16 nmol/nm 2 for CIP-SNPs, and (10.4 ± 2.0) × 10 −16 nmol/nm 2 for NOR-SNPs. These data compare well with those obtained using PFAA photocoupling chemistry (19.8 × 10 −6 nmol/nm 2 for trehalose-modified SNPs), 20 or the CuAAC reaction (13.0 × 10 −16 nmol/nm 2 for mannose-modified SNPs), 22 demonstrating high efficiency of the reaction.…”

A Multi-Method Approach for Quantification of Surface Coatings on Commercial Zinc Oxide Nanomaterials

“…Nevertheless, it is rare that the surface groups are quantified, particularly for commercial nanomaterials, and in some cases the chemical nature of the surface and the presence of possible contaminants are not addressed [4]. It should be noted that this is not due to a lack of methods for surface chemistry analysis [5][6][7][8][9][10][11][12][13][14][15][16]. However, the choice of appropriate method and its range of applicability and sensitivity are frequently not clear.…”

Quantification of amine functional groups on silica nanoparticles: a multi-method approach

“…[21][22][23] In the present study we compare the results from two colorimetric assays for quantication of accessible surface amines to results obtained by labeling amines with tri-uoromethylated probes that provide high sensitivity for XPS and quantitative solid state 19 F NMR. 2,5,19,24,25 The two colorimetric assays are based on the reaction of ninhydrin with primary amines to generate a dye that is released from the surface and quantied in the supernatant and the reaction of an aldehyde with surface amines to generate an imine product that can be cleaved for quantication aer isolation of the NPs. These two assays may differ in their ability to detect surfaceaccessible amines, particularly at high surface coverage where steric effects are expected to become important.…”