Fe(III)-Induced FRET-On: Energy Transfer from Rhodamine 6G to Nile Red

Abstract

excimer/exciplex formation, 4 imine isomerization, 5 chelationenhanced fluorescence (CHEF), 6 and fluorescence resonance energy transfer (FRET).7 Among them, at present, the FRET is an active field in chemistry and biochemistry due to its potential practical benefits in cell physiology, optical therapy, as well as selective and sensitive sensing toward target molecular or ionic species. FRET arises from an excited-state energy interaction between two fluorophores in which a donor fluorophore, in its excited-state, transfers energy to an acceptor fluorephore. Accordingly, it is strongly influenced by the distance between donor and acceptor, the extent of spectral overlap between donor emission and acceptor absorption spectrum (Figure 1).As a fluorophore unit, rhodamine 6G has attracted considerable interest from chemists on account of its excellent photophysical properties. The spirolactam ring form of rhodamine derivatives is non-fluorescent and colorless, whereas its ringopened form gives a strong fluorescence and a pink color. In general, a rhodamine derivative shows a pink color change and strong fluorescence upon addition of specific metal ion or in acidic condition. Thereby, the rhodamine fluorophore can be an ideal framework to construct OFF-ON FRET system for the specific metal ion or pH variation. 8 For the FRET-based chemosensors for specific metal ions, we have previously reported a donor (pyrene, dansyl, or coumarin)-acceptor (rhodamine) fluorophore in conjunction with a spacer tris(2-aminoethyl)-amine (tren).9 The tren-spaced rhodamine

Fluorescence Resonance Energy Transfer in a Binary Organic Nanoparticle System and Its Application

“…When used in fluorescence sensing, it has the characteristic of distance-dependent emission, two-color fluorescence correlation, and good sensitivity . Nowadays, numerous FRET-based fluorescent probes including conjugated polymers nanoparticles, small molecules, water-soluble conjugated polymer, quantum dots, and upconversion nanoparticles (NPs) have been exploited to detect either biomolecules such as proteins and nucleic acids or chemicals such as toxins, active oxygen species, and metal ions. − Most of these fluorescent probes are small molecules or water-soluble conjugated polymers. ,− However, such molecular probes often suffer from low photostability such as photoblinking, photobleaching, and photooxidation. , …”

Nile Red Derivative-Modified Nanostructure for Upconversion Luminescence Sensing and Intracellular Detection of Fe3+ and MR Imaging

“…Since the fluorescent emission of Nile red exhibits a large bathochromic shift in polar media, it can be used as a probe to indicate the polarity of the environment to which it is attached. , As the fluorescence yield is low, the probe of Nile red or its derivative has been less studied. Up to now, many available fluorescent probes have been developed with a change in fluorescence intensity under the rich microenvironment of Fe 3+ . − However, to the best of our knowledge, the intracellular probe of Fe 3+ ion detection based on Nile red derivative (NRD) have not been reported in the open literature to date . In addition, most of the reported fluorescent probes exhibit emission under excitation of UV or visible light, which could cause damage to healthy cells.…”

“…18−20 However, to the best of our knowledge, the intracellular probe of Fe 3+ derivative (NRD) have not been reported in the open literature to date. 21 In addition, most of the reported fluorescent probes exhibit emission under excitation of UV or visible light, which could cause damage to healthy cells. Moreover, most of the Fe 3+ -selective probes are insoluble in water because of their organic nature.…”