A reversible “turn-off-on” fluorescent probe for real-time visualization of mercury(II) in environmental samples and its biological applications

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

“…These results confirmed the Tb(III)-phen-AgNPs system formation and energy transfer from Tb(III)-phen to AgNPs by the FRET process. 27,28 The Stern-Volmer equation was applied to a fluorescence quenching data analysis: 52,53…”

“…This method provides useful information on the nature of the interaction between fluorophore and quencher and is widely applied to the determination/detection of metal and inorganic ions (including Fe 2+ , Fe 3+ , Hg 2+ , Al 3+ , F -, citrate and chromate), biomolecules (such as amino acids, DNA, RNA, ATP, lysozyme, glucose, glutathione and cholesterol), pesticides, heparin, anti-cancer drugs and etc. [25][26][27][28][29][30][31][32][33][34] Currently, most fluorescence quenching methods are based on the use of nanomaterials, which are performed in different strategies, including quenching (turn-off ), quenching-recovery (turn offon), turn on-off, turn on-off-on and turn off-on-off. Among these different modes, based on turn off-on fluorescence approaches have been widely used for the determination of different drugs and compounds in biological samples.…”

“…These methods are very sensitive, rapid, simple, inexpensive and free from interferences. 27,28,[31][32][33]35 In a typical turn off-on based sensing system, the fluorescence intensity of a donor fluorophore is first quenched by nanomaterials, which are commonly used as energy acceptors, and then gradually and linearly restored by introducing competing analytes, and as a result, a turn off-on detection signal is generated. Indeed, due to the strong and specific bindings between analyte molecules and nanomaterials (quenching agents), the interaction between donor and acceptor molecules is weaken, consequently the quenched fluorescence of the system is gradually recovered.…”

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

“…In contrast, fluorimetric methods are very sensitive and selective, inexpensive and present a short run time, use simple instruments, with easy operation and good reproducibility. [ 27–30 ]…”

“…[ 27,28,37 ] Alternatively, with the advancement of nanoscience and the development of nanosensors as fluorescent probes with unique photophysical and chemical characteristics, fluorescence‐based methods have become a suitable alternative to other analytical methods for analysis of different chemical and biochemical compounds. [ 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).…”