A photochemically initiated chemistry for coupling underivatized carbohydrates to gold nanoparticles

Abstract

The sensitive optoelectronic properties of metal nanoparticles make nanoparticle-based materials a powerful tool to study fundamental biorecognition processes. Here we present a new and versatile method for coupling underivatized carbohydrates to gold nanoparticles (Au NPs) via the photochemically induced reaction of perfluorophenylazide (PFPA). A one-pot procedure was developed where Au NPs were synthesized and functionalized with PFPA by a ligand-exchange reaction. Carbohydrates were subsequently immobilized on the NPs by a fast light activation. The coupling reaction was efficient, resulting in high coupling yield as well as high ligand surface coverage. A colorimetric system based on the carbohydrate-modified Au NPs was used for the sensitive detection of carbohydrate-protein interactions. Binding and cross-reactivity studies were carried out between carbohydrate-functionalized Au NPs and lectins. Results showed that the surfacebound carbohydrates not only retained their binding affinities towards the corresponding lectin, but also exhibited affinity ranking consistent with that of the free ligands in solution.

Glyconanoparticles for colorimetric bioassays

“…81 a) b) Wang et al found that the sensitivity of mannose-functionalised nanoparticles towards ConA increased with the spacer length. 82 The authors prepared the glyconanoparticles using a photocoupling method, as previously described in this review, 66 and more flexible spacer linkage exhibited the lowest limit of detection. 82 While these results appear to contradict previous work, 52,76,78 it is possible that the flexibility of the anchor chain is an additional important feature for the targeting and sensitive detection of proteins with glyconanoparticles.…”

“…Aggregation studies in the presence of ConA were performed to investigate whether the recognition ability of the carbohydrates changes upon coupling. 66 The coupling of carbohydrates using microwave radiation is another alternative for the functionalisation of gold nanoparticles. 68 In this example, gold nanoparticles were first functionalised with di(N-succinimidyl)3,3'-dithiodipropionate and then reacted with 2-mercaptoethylamine hydrochloride via succinimidyl-amino covalent binding.…”

“…20 nm) with perfluorophenylazide disulfide, the nitrene species of which were photochemically activated to couple the carbohydrates of interest. 66,67 This method was used to synthesise monosaccharide-and disaccharide-functionalised gold nanoparticles. Aggregation studies in the presence of ConA were performed to investigate whether the recognition ability of the carbohydrates changes upon coupling.…”

Dynamic Nanoplatforms in Biosensor and Membrane Constitutional Systems

“…The intrinsic photoluminescence of quantum dots has been utilized for specific protein sensing [68,69]. Composites of the aforementioned gold NP, silver NP and quantum dots usually with silica or polymeric materials have also been employed as described in a recent review [70] The multivalent presentation of carbohydrate ligands significantly enhances the binding affinity toward lectins by several orders of magnitude in comparison to the free ligands in solution and strongly depends on the type and length of the spacer linkage and ligand density [71].…”

Stereoisomerism effect on sugar–lectin binding of self-assembled glyco-nanoparticles of linear and brush copolymers

“…Considering the fact that many of the currently known CRDs only bind to the terminal oligosaccharides of glycans, glycopolymers with repeating pendent units show their great advantage in mimicking these terminal oligosaccharides [9][10][11][12], which is important to further exploration on both of the known and unknown carbohydrate-protein interactions. Meanwhile, the artificial glycopolymers and glyco-nanoparticles have show enhancement multivalent binding behavior of carbohydrate and lectins [13][14][15][16][17][18][19].…”