A “turn-on” fluorescence sensor for ascorbic acid based on graphene quantum dots via fluorescence resonance energy transfer

Abstract

For the first time, a FRET nanosensor for AA was developed using GQDs as the energy donors and SQA-iron(iii) as the energy acceptors.

An Overview of Optical and Electrochemical Sensors and Biosensors for Analysis of Antioxidants in Food during the Last 5 Years

“…By oxidation-depletion between iron(III) and AA, the fluorescence of GQDs could be sensitively turned on by AA. The linear range and LOD were 1–95 µM and 0.2 µM, respectively [ 73 ]. Also, by using of the orange emission GrQDs, a fluorescence turn-on analysis for identification of ascorbic acid (AA) was reported.…”

“…They reported the requirement of very low consumption of reagents in this method compared to the photo-bleaching method [ 69 ]. In another study, a FRET-based nanosensor with fluorescence turn-on analysis for the ascorbic acid recognition was reported [ 73 ]. Compared with a similar study [ 76 ] that used GrQDs/CQDs for detecting ascorbic acid, the FRET-based nanosensor method did not need the usage of highly toxic metals (e.g., Cr(VI)) and overpriced enzymes.…”

A rapid, simple and ultrasensitive spectrofluorimetric method for the direct detection of metformin in real samples based on a nanoquenching approach

“…[ 29,30,33,38 ] Usually, these fluorescent nanoprobes act as fluorescence sensors based on different strategies and modes. The most important of which include quenching (turn off), [ 31,39 ] enhancement (turn on), [ 40–42 ] quenching–recovery (turn off–on), [ 43–49 ] turn on–off, [ 50 ] turn on–off–on, [ 51,52 ] turn off–on–off [ 53 ] and metal enhanced fluorescence (MEF). [ 54 ]…”

“…Several mechanisms are responsible for fluorophore fluorescence quenching in the above‐mentioned modes such as fluorescence resonance energy transfer (FRET), photo‐induced electron transfer (PET) and inner filter effect (IFE). [ 28,33,40,42,44,46,51,54 ] FRET is a physical and distance‐dependent process in which energy is transferred from an excited donor molecule to an acceptor molecule via nonradiation, through‐space dipole–dipole interactions. This important process occurs when two donor and acceptor molecules are within the Förster distance (< 8.0 nm), and there is a great overlap between the emission spectra of donor fluorophore and the absorption spectra of the acceptor molecule.…”

A Sensitive, Simple and Direct Determination of Pantoprazole Based on a “Turn off-on” Fluorescence Nanosensor by Using Terbium-1,10-phenanthroline-silver Nanoparticles

“…Various mechanisms can decrease the fluorescence intensity of the fluorophore in these system such as fluorescence resonance energy transfer (FRET), photo induced electron transfer (PET) and inner filter effect (IFE). 26,31,[36][37][38] Fluorescent biosensors based on nanomaterials, especially metal nanoparticles (MNPs; such as gold (Au) and silver (Ag) NPs) and Au and Ag nanoclusters (NCs) for the determination of biological samples, has recently gained much more attention. These biosensors compared to traditional fluorescent probes give some advantages involving high quenching coefficients, broad absorption bands, ease of synthesis and their surface chemical modification, high photostability, photobleaching, good solubility and because of their unique electronic and optical properties, act as an ideal of either the acceptors or donors for the FRET process.…”