Highly sensitive fluorescence detection of glycoprotein based on energy transfer between CuInS2 QDs and rhodamine B

Spectral-Time Multiplexing in FRET Complexes of AgInS2/ZnS Quantum Dot and Organic Dyes

Nowadays, multiplex analysis is very popular, since it allows to detect a large number of biomarkers simultaneously. Traditional multiplex analysis is usually based on changes of photoluminescence (PL) intensity and/or PL band spectral positions in the presence of analytes. Using PL lifetime as an additional parameter might increase the efficiency of multiplex methods. Quantum dots (QDs) can be used as luminescent markers for multiplex analysis. Ternary in-based QDs are a great alternative to the traditional Cd-based one. Ternary QDs possess all advantages of traditional QDs, including tunable photoluminescence in visible range. At the same time ternary QDs do not have Cd-toxicity, and moreover they possess long spectral dependent lifetimes. This allows the use of ternary QDs as a donor for time-resolved multiplex sensing based on Förster resonance energy transfer (FRET). In the present work, we implemented FRET from AgInS₂/ZnS ternary QDs to cyanine dyes absorbing in different spectral regions of QD luminescence with different lifetimes. As the result, FRET-induced luminescence of dyes differed not only in wavelengths but also in lifetimes of luminescence, which can be used for time-resolved multiplex analysis in biology and medicine.

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

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 %.

Boronate affinity material-based sensors for recognition and detection of glycoproteins

This review comprehensively presents the current overview and development potential of BAMs-based sensors for glycoprotein recognition and detection.

A novel fluorescent turn-on biosensor based on QDs@GSH-GO fluorescence resonance energy transfer for sensitive glutathione S-transferase sensing and cellular imaging

A novel fluorescent turn-on biosensor based on fluorescence resonance energy transfer (FRET) from GSH functionalized Mn-doped ZnS QDs to graphene oxide (GO) was constructed to determine glutathione S-transferases (GSTs) in live cells and human urine. The QDs@GSH is adsorbed on the GO surface via hydrogen bonding interaction between the GSH on the surface of QDs@GSH and GO, and as a result, fluorescence quenching of the QDs@GSH takes place because of FRET. The FRET efficiency from QDs@GSH to GO was calculated to be 86.3%. However, in the presence of GSTs, the FRET process could be inhibited by the specific interaction between the GSH on the surface of QDs@GSH and GSTs, which would keep the QDs@GSH far away from the GO surface, leading to the recovery of the fluorescence. The proposed sensor exhibited high sensitivity, selectivity, and excellent specificity in the buffer, live cells and human urine for the detection of GSTs. Under the physiological conditions (pH 7.4), dissociation constants and the detection limit of GST and ATP6 V1F (a GST-tagged protein) were estimated to be 8.0 × 10^-9 M, 2.1 × 10^-10 M and 3.5 × 10^-9 M, 7.2 × 10^-11 M, respectively. The presented method has been successfully utilized for the determination of the GSTs in live cells and human urine without any complicated pretreatment and the recovery was in the range of 80%-90%.