Near-Infrared Probes Designed with Hemicyanine Fluorophores Featuring Rhodamine and 1,8-Naphthalic Derivatives for Viscosity and HSA Detection in Live Cells.

This paper presents the development of near-infrared (NIR) fluorescent probes, and , engineered from hemicyanine dyes with 1,8-naphthalic and rhodamine derivatives for optimized photophysical properties and precise mitochondrial targeting. Probes and exhibit absorption peaks at 737 nm and low fluorescence in phosphate-buffered saline (PBS) buffer. Notably, their fluorescence intensities, peaking at 684 () and 702 nm (), increase significantly with viscosity, as demonstrated through glycerol-to-PBS ratio experiments.

Near-Infrared Visualization of NAD(P)H Dynamics in Live Cells and Larvae Using a Coumarin-Based Pyridinium Fluorescent Probe.

A near-infrared fluorescent probe, , was designed by substituting the carbonyl group of the coumarin dye's lactone with a 4-cyano-1-methylpyridinium methylene group and then attaching an electron-withdrawing NADH-sensing methylquinolinium acceptor via a vinyl bond linkage to the coumarin dye at the 4-position. The probe exhibits primary absorption maxima at 603, 428, and 361 nm, and fluoresces weakly at 703 nm. The addition of NAD(P)H results in a significant blue shift in the fluorescence peak from 703 to 670 nm, accompanied by a substantial increase in fluorescence intensity.

Dynamic insights into mitochondrial function: Monitoring viscosity and SO levels in living cells.

Mitochondria, central organelles pivotal for eukaryotic cell function, extend their influence beyond ATP production, encompassing roles in apoptosis, calcium signaling, and biosynthesis. Recent studies spotlight two emerging determinants of mitochondrial functionality: intramitochondrial viscosity and sulfur dioxide (SO) levels. While optimal mitochondrial viscosity governs molecular diffusion and vital processes like oxidative phosphorylation, aberrations are linked with neurodegenerative conditions, diabetes, and cancer.

Syntheses and Applications of Coumarin-Derived Fluorescent Probes for Real-Time Monitoring of NAD(P)H Dynamics in Living Cells across Diverse Chemical Environments.

Fluorescent probes play a crucial role in elucidating cellular processes, with NAD(P)H sensing being pivotal in understanding cellular metabolism and redox biology. Here, the development and characterization of three fluorescent probes, , , and , based on the coumarin platform for monitoring of NAD(P)H levels in living cells are described. Probes and incorporate a coumarin-cyanine hybrid structure with vinyl and thiophene connection bridges to 3-quinolinium acceptors, respectively, while probe introduces a dicyano moiety for replacement of the lactone carbonyl group of probe which increases the reaction rate of the probe with NAD(P)H.

Near-infrared Absorption and Emission Probes with Optimal Connection Bridges for Live Monitoring of NAD(P)H Dynamics in Living Systems.

Two NAD(P)H-biosensing probes consisting of 1,3,3-trimethyl-3H-indolium and 3-quinolinium acceptors, linked by thiophene, , and 3,4-ethylenedioxythiophene, , bridges are detailed. We synthesized probes and , replacing the thiophene connection in probe with phenyl and 2,1,3-benzothiadiazole units, respectively. Probe was prepared by substituting probe 's 3-quinolinium unit with a 1-methylquinoxalin-1-ium unit.

Sensitive monitoring of NAD(P)H levels within cancer cells using mitochondria-targeted near-infrared cyanine dyes with optimized electron-withdrawing acceptors.

A series of near-infrared fluorescent probes, labeled A to E, were developed by combining electron-rich thiophene and 3,4-ethylenedioxythiophene bridges with 3-quinolinium and various electron deficient groups, enabling the sensing of NAD(P)H. Probes A and B exhibit absorptions and emissions in the near-infrared range, offering advantages such as minimal interference from autofluorescence, negligible photo impairment in cells and tissues, and exceptional tissue penetration. These probes show negligible fluorescence when NADH is not present, and their absorption maxima are at 438 nm and 470 nm, respectively.

Thiophene-based organic dye with large Stokes shift and deep red emission for live cell NAD(P)H detection under varying chemical stimuli.

We report a novel method for synthesizing red and deep red cyanine dyes with large Stokes shifts, probes A and B, for live cell NAD(P)H detection. The probes were prepared using thiophene-based organic dyes featuring a π-conjugated bridge of thiophene and 3,4-ethylenedioxythiophene units linking the 1-methylquinolinium acceptor and formyl acceptor, respectively. These probes display weak absorption peaks at 315 nm (A) and 334 nm (B) and negligible fluorescence in the absence of NADH.

Near-infrared rhodol dyes bearing salicylaldehyde moieties for ratiometric pH sensing in live cells during mitophagy and under hypoxia conditions.

We describe a simple but efficient approach to make fluorescent probes A and B based on rhodol dyes incorporated with salicyaldehyde moiety for monitoring pH changes in mitochondria under oxidative stresses and hypoxia conditions, and for tracking mitophagy processes. Probes A and B possess p values (p ≈ 6.41 and 6.

An effective fluorescent probe for detection of phosgene based on naphthalimide dyes in liquid and gaseous phases.

A fluorescent probe was developed for the detection of phosgene based on 1,8-naphthalimide, of which o-diaminobenzene was used as the recognition moiety. The probe does not fluoresce due to nonradiative decay. The probe reacts rapidly with phosgene via an intramolecular cyclization reaction, which induces large fluorescence due to increased rigidity in the resulting molecule and a low detection limit (0.

Near-Infrared Fluorescent Probes with Amine-Incorporated Xanthene Platforms for the Detection of Hypoxia.

Three fluorescent probes , , and that function in the near-infrared wavelengths and utilize pseudo xanthene platforms with an oxygen atom at the 10-position replaced by a [Me-N] group have been created to identify hypoxia via nitroreductase determinations at the 0.04, 0.10, and 0.

Near-infrared fluorescent probe based on rhodamine derivative for detection of NADH in live cells.

A near-infrared fluorescent probe was prepared for selective detection of reduced nicotinamide adenine dinucleotide (NADH) in live cells. The probe turns off the fluorescence with a closed spironolactone switch. However, reduction of the probe by NADH turns on fluorescence at 740 nm.

A two-photon fluorogenic probe based on a coumarin schiff base for formaldehyde detection in living cells.

A novel two-photon fluorogenic probe has been developed to detect formaldehyde with fast response, low cytotoxicity, and excellent selectivity. This probe exhibits a strong turn-on fluorescence response to formaldehyde under excitation at 370 nm and has been successfully applied to detect formaldehyde in living cells. Theoretical calculations at the B3LYP/6-31 + G(d,p), APFD/6-311++G, and APFD/6-311 + G(2d,p) levels of theory for the absorption and emission wavelengths of the probes were in agreement with those obtained experimentally.

A ratiometric near-infrared fluorescent probe based on a novel reactive cyanine platform for mitochondrial pH detection.

A near-infrared reactive cyanine platform (probe A) was prepared by condensation of 9-chloro-1,2,3,4-tetrahydro-10-methyl-acridinium iodide with Fisher's aldehyde. A near-infrared fluorescent probe (probe B) was prepared by modifying a reactive chlorine atom of probe A with tert-butyl(2-aminoethyl)carbamate through a substitution reaction. The deprotection of the Boc group of probe B was achieved under an acidic condition, affording an amine-functionalized cyanine dye (probe C).

Ratiometric Detection of Glutathione Based on Disulfide Linkage Rupture between a FRET Coumarin Donor and a Rhodamine Acceptor.

Abnormal levels of glutathione, a cellular antioxidant, can lead to a variety of diseases. We have constructed a near-infrared ratiometric fluorescent probe to detect glutathione concentrations in biological samples. The probe consists of a coumarin donor, which is connected through a disulfide-tethered linker to a rhodamine acceptor.

Ratiometric Near-Infrared Fluorescent Probes Based on Hemicyanine Dyes Bearing Dithioacetal and Formal Residues for pH Detection in Mitochondria.

Ratiometric near-infrared fluorescent probes ( and ) have been prepared for pH determination in mitochondria by attaching dithioacetal and formal residues onto a hemicyanine dye. The reactive formyl group on probe allows for retention inside mitochondria as it can react with a protein primary amine residue to form an imine under slightly basic pH 8.0.

A near-infrared fluorescent probe based on a hemicyanine dye with an oxazolidine switch for mitochondrial pH detection.

A near-infrared fluorescent probe (AH+) has been prepared by incorporating an oxazolidine switch into a near-infrared hemicyanine dye. The probe shows fast and sensitive responses to pH from an oxazolidine switch to the hemicyanine dye upon pH decreases from 10.0 to 5.

Cell Membrane-Specific Fluorescent Probe Featuring Dual and Aggregation-Induced Emissions.

A cell membrane-specific fluorescent probe was prepared by conjugating a coumarin dye with a tetraphenylethene (TPE) derivative through an α,β-unsaturated ketone connection. The probe has two absorptions: one from the TPE moiety at 300 nm and a second one due to the coumarin moiety at 458.5 nm.

Ratiometric fluorescent probes based on through-bond energy transfer of cyanine donors to near-infrared hemicyanine acceptors for mitochondrial pH detection and monitoring of mitophagy.

Two ratiometric near-infrared fluorescent probes have been developed to selectively detect mitochondrial pH changes based on highly efficient through-bond energy transfer (TBET) from cyanine donors to near-infrared hemicyanine acceptors. The probes consist of identical cyanine donors connected to different hemicyanine acceptors with a spirolactam ring structure linked via a biphenyl linkage. At neutral or basic pH, the probes display only fluorescence of the cyanine donors when they are excited at 520 nm.

Near-Infrared Hybrid Rhodol Dyes with Spiropyran Switches for Sensitive Ratiometric Sensing of pH Changes in Mitochondria and melanogaster First-Instar Larvae.

Near-infrared hybrid rhodol dyes (probes and ) for sensitive ratiometric visualization of pH changes were prepared by incorporating hemicyanine dyes into traditional rhodol dyes. This approach was based on -conjugation changes involving a rhodol hydroxyl group as a spiropyran switch upon pH changes. Electronic spectra of probes - and - contain sharp absorption peaks at 535 nm and fluorescence peaks at 558 nm with similar -conjugation and a closed spiropyran form at a basic pH of 10.

Near-infrared fluorescent probes with BODIPY donors and rhodamine and merocyanine acceptors for ratiometric determination of lysosomal pH variance.

Three fluorescent probes have been developed by conjugating three different BODIPY donors to rhodamine and merocyanine acceptors for ratiometric determination of lysosomal pH variations. Probe consists of a 1,3,5,7-tetramethyl-BODIPY donor and a near-infrared rhodamine acceptor bearing a lysosome-targeting morpholine residue. Probe is composed of a 3,5-dimethyl-BODIPY donor and a near-infrared rhodamine acceptor modified with an -phenylenediamine residue.

Near-infrared fluorescent probes based on TBET and FRET rhodamine acceptors with different p values for sensitive ratiometric visualization of pH changes in live cells.

Three near-infrared ratiometric fluorescent probes () based on TBET and FRET near-infrared rhodamine acceptors with different p values were designed and synthesized to achieve sensitive ratiometric visualization of pH variations in lysosomes in visible and near-infrared channels. Tetraphenylethene (TPE) was bonded to near-infrared rhodamine dyes through short electrical π -conjugation linkers to prevent an aggregation-caused quenching (ACQ) effect and allow highly efficient energy transfer of up to 98.9% from TPE donors to rhodamine acceptors.

Fluorescent probes with high pKa values based on traditional, near-infrared rhodamine, and hemicyanine fluorophores for sensitive detection of lysosomal pH variations.

Sterically hindered fluorescent probes (A-C) have been developed by introducing 2-aminophenylboronic acid pinacol ester to a traditional, A, a near-infrared rhodamine dye, B, and a near-infrared hemicyanine dye, C, forming closed spirolactam ring structures. Probe A was non-fluorescent under basic pH conditions whereas probes B and C were moderately fluorescent with fluorescence quantum yields of 9% and 5% in pH 7.4 PBS buffer containing 1% ethanol, respectively.