Fluorescent Labelling of Glycans with FRET‐Based Probes in a Gold(III)‐Mediated Three‐Component Coupling Reaction

Abstract

Single‐site multifunctionalization of glycans is of importance in biological studies considering its crucial role in mediating biological events and human diseases. In this paper, a novel approach for multifunctional labelling of glycans has been developed featuring the use of fluorescence resonance energy transfer‐based (FRET‐based) probes for fluorescent labelling of glycans through a gold(III)‐mediated three‐component coupling reaction. Oxidation of glycans into aldehydes followed by the A3‐coupling reaction with FRET‐based probes resulted in the single‐site formation of fluorescent propargylamine products. The conversion of labelled glycans can be revealed by ratiometric analysis of the FRET signals. This labelling approach results in multifunctionalization of glycans with high selectivity and conversion between 66 and 69 %.

Isoindolium‐Based Allenes: Reactivity Studies and Applications in Fluorescence Temperature Sensing and Cysteine Bioconjugation

“…[23][24][25] Owing to the ready elaboration of the allene and amine moieties of the isoindolium-based allene 1, we hypothesized that a FRET dye pair could be linked by the reaction of a dyelinked isoindolium-based allene with a dye-linked thiol, giving an isoindolium-based vinyl sulfide linked to two dyes as a FRET-based fluorescent probe. Along with our interest in the development of fluorescent sensors, [26][27][28][29] we envisioned that thermal cleavage of the fluorescent isoindoliumbased vinyl sulfide to give a dye-linked indanone and dyelinked amine would provide a novel FRET-based temperature sensing system (Scheme 4).…”

“…In line with our previous studies on FRET-based probes, [29] coumarin and fluorescein were chosen as the fluorophores for the synthesis of the FRET-based sensor. Considering the spectral overlap between the emission wavelength of coumarin and the excitation wavelength of We examined the photophysical properties of coumarinlinked allene 10, fluorescein-linked thiol 11 and vinyl sulfide 5 (Figure 1).…”

Controlled Supramolecular Assemblies of Chiral Cyclometalated Gold (III) Amphiphiles in Aqueous Media

“…Gold complexes have been intensively investigated for applications in catalysis, [25–29] optoelectronic materials, [30,31] and Bioconjugation strategies, [32–37] due to the excellent aqueous stability. Amphiphilic designs of gold (III) complexes were firstly reported by Che in 2016, [38] to use polyethene glycol (PEG) based cyclometalated gold (III) complexes for formation nano‐micelles enabling in‐vitro phototoxicity.…”

Controlled Supramolecular Assembly of Gold (III) Amphiphiles in Aqueous Media

“…Previously, we have developed a class of gold (III) complexes for versatile applications ranging from catalysis [34,35] to bioconjugation methodologies. [36][37][38] These cyclometalated gold (III) complexes provide a synthetic toolbox for chemoselective modification of biomolecules in aqueous media. Furthermore, we have demonstrated that the photoresponsive molecular amphiphiles, such as motor amphiphiles, can be potentially developed to supramolecular actuators and stimuli-responsive supramolecular assemblies in aqueous media.…”

“…Previously, we have developed a class of gold (III) complexes for versatile applications ranging from catalysis [34,35] to bioconjugation methodologies [36–38] . These cyclometalated gold (III) complexes provide a synthetic toolbox for chemoselective modification of biomolecules in aqueous media.…”