Rhodamine Derivative Research Articles

Efficient Enhancement of Electron Transport and Collection Capability in PTB7:PC71 BM-based Solar Cells Enabled by Sulforhodamine Cathode Interlayers.

Development of low-cost water-/alcohol-soluble interfacial materials is a crucial issue to promote the commercialization of polymer solar cells (PSCs). Herein, two derivatives of low-cost rhodamine, called sulforhodamine 101 (SR101) and sulforhodamine B (SRB), are applied as cathode interfacial layers (CILs) to effectively improve the charge-carrier transportation and collection, reduce the work function (WF) of Al counter electrode, and decrease the series resistance and charge recombination in the PSCs. As a result, SR101-based devices show excellent performance with the highest power conversion efficiency (PCE) of 9.10 %, superior to that of both the control devices with MeOH/Al and Ca/Al. Notably, sulforhodamine is commercially available with low cost and great solution-processability. This work demonstrates that sulforhodamine has a great potential as a CIL material,which is suitable for the large-area fabrication process and commercialization of highly efficient PSCs.

Rare Crystal Structure of Open Spirolactam Ring along with the Closed-Ring Form of a Rhodamine Derivative: Sensing of Cu2+ Ions from Spinach.

Crystal structures of a rhodamine derivative in its closed and open spirolactam ring forms were developed, which allows selective and sensitive detection of Cu2+ ions at a micromolar range in neutral medium. The chemosensing properties of the probe through a pentacoordinate Cu2+ ions were proven by spectroscopic and theoretical analysis. The spirolactam ring opening as the Cu2+ selective sensor was applied to spinach (Spinacia oleracea) to estimate the accumulation of copper as copper(II) in the plant.

Investigation of Oxazine and Rhodamine Derivatives as Peripheral Nerve Tissue Targeting Contrast Agent for In Vivo Fluorescence Imaging.

Accidental nerve transection or injury is a significant morbidity associated with many surgical interventions, resulting in persistent postsurgical numbness, chronic pain, and/or paralysis. Nerve-sparing can be a difficult task due to patient-to-patient variability and the difficulty of nerve visualization in the operating room. Fluorescence image-guided surgery to aid in the precise visualization of vital nerve structures in real time during surgery could greatly improve patient outcomes. To date, all nerve-specific contrast agents emit in the visible range. Developing a near-infrared (NIR) nerve-specific fluorophore is poised to be a challenging task, as a NIR fluorophore must have enough "double-bonds" to reach the NIR imaging window, contradicting the requirement that a nerve-specific agent must have a relatively low molecular weight to cross the blood-nerve-barrier (BNB). Herein we report our efforts to investigate the molecular characteristics for the nerve-specific oxazine fluorophores, as well as their structurally analogous rhodamine fluorophores. Specifically, optical properties, physicochemical properties and their in vivo nerve specificity were evaluated herein.

Selective Detection of Hg2+ Ions with Boron Dipyrromethene-Based Fluorescent Probes Appended with a Bis(1,2,3-triazole)amino Receptor.

By using a copper-promoted alkyne-azide cycloaddition reaction, two boron dipyrromethene (BODIPY) derivatives bearing a bis(1,2,3-triazole)amino receptor at the meso position were prepared and characterized. For the analogue with two terminal triethylene glycol chains, the fluorescence emission at 509 nm responded selectively toward Hg2+ ions, which greatly increased the fluorescence quantum yield from 0.003 to 0.25 as a result of inhibition of the photoinduced electron transfer (PET) process. By introducing two additional rhodamine moieties at the termini, the resulting conjugate could also detect Hg2+ ions in a highly selective manner. Upon excitation at the BODIPY core, the fluorescence emission of rhodamine at 580 nm was observed and the intensity increased substantially upon addition of Hg2+ ions due to inhibition of the PET process followed by highly efficient fluorescence resonance energy transfer (FRET) from the BODIPY core to the rhodamine moieties. The Hg2+ -responsive fluorescence change of these two probes could be easily seen with the naked eye. The binding stoichiometry between the probes and Hg2+ ions in CH3 CN was determined to be 1:2 by Job's plot analysis and 1 H NMR titration, and the binding constants were found to be (1.2±0.1)×1011 m-2 and (1.3±0.3)×1010 m-2 , respectively. The overall results suggest that these two BODIPY derivatives can serve as highly selective fluorescent probes for Hg2+ ions. The rhodamine derivative makes use of a combined PET-FRET sensing mechanism which can greatly increase the sensitivity of detection.

Rhodamine Derivative- Based Cellulose Acetate Electrospun Colorimetric Sensor for Cu2+ Sensing in Water: Effects of Alkaline Treatment

This is the first investigation of a rhodamine B derivative (RBD)/cellulose acetate (CA) colorimetric test strip for Cu2+ sensing in water. The test strip allowed both semi-quantitative naked-eye detection and quantitative detection when spectroscopy was applied. A chemosensor, RBD, was doped into a CA solution and this was electrospun to produce a test strip. The average diameter of the electrospun fibers was 750±270 nm. The nonwoven test strip changed from off-white to pink when exposed to aqueous Cu2+ solutions. A linear relationship was found between the color strength of the test strip and the Cu2+ concentration (20–300 ppm, R2=0.989). The limit of detection (LOD) was 18 ppm. Alkaline treatment of the electrospun sample with sodium hydroxide produced partial deacetylation of the CA, reducing the number of acetyl groups while increasing the number of hydroxyl groups in the fibrous structure. Fiber swelling and improved wettability of the solid sensor was also observed. The treated sensor responded approximately 33 times faster to Cu2+ than the untreated sensor. When tested with Cu2+, the sensor produced K/S values approximately 5–10 times greater than when tested with Mn2+, Pb2+, Cd2+, Ni2+, Zn2+ or Sn2+, and three times greater than Fe2+. The electrospun sensor showed a slight improvement in Cu2+ adsorption after alkaline treatment.

Rhodamine derivatives as selective“naked-eye” colorimetric and fluorescence off-on sensor for Hg2+ in aqueous solution and its applications in bioimaging

Three new rhodamine based probes 1, 2, 3 were synthesized and acted as fluorescence probes for Hg2+ detection in Tris - HCl/C2H5OH (v: v = 3: 7, 10 mM, pH = 7.2). Hg2+ induced a colorless solution of probes 1, 2, 3 to turn to naked-eye visible pink with a 44 - fold fluorescence enhancement at 576 nm. Probes 1, 2, 3 are highly selective to Hg2+ over other tested cations with the detection limits are 18 nM, 16 nM, 56 nM, respectively. What's more, the binding constants between probes 1, 2, 3 and Hg2+ are 5.0 × 106 M−1, 1.8 × 106 M−1, 1.5 × 106 M−1, respectively. The different detection limits and binding constants of probes 1, 2, 3 and Hg2+ may depend on the coordination of probes 1, 2, 3. The recognition mechanism of probes 1, 2, 3 towards Hg2+ is determinated by ESI - MS, DFT and indicates that a ring-opening of the spirolactam unit and formed complexes between probes 1, 2, 3, resulting in chromogenic and fluorogenic changes. The probes 1, 2, 3 could be applied in both environmental and Hg2+ polluted samples due to the instantly and reversible ‘‘off-on’’ Hg2+ response, well cell permeability, cell imaging ability.

Labeling Strategies Matter for Super-Resolution Microscopy: A Comparison between HaloTags and SNAP-tags

SummarySuper-resolution microscopy requires that subcellular structures are labeled with bright and photostable fluorophores, especially for live-cell imaging. Organic fluorophores may help here as they can yield more photons—by orders of magnitude—than fluorescent proteins. To achieve molecular specificity with organic fluorophores in live cells, self-labeling proteins are often used, with HaloTags and SNAP-tags being the most common. However, how these two different tagging systems compare with each other is unclear, especially for stimulated emission depletion (STED) microscopy, which is limited to a small repertoire of fluorophores in living cells. Herein, we compare the two labeling approaches in confocal and STED imaging using various proteins and two model systems. Strikingly, we find that the fluorescent signal can be up to 9-fold higher with HaloTags than with SNAP-tags when using far-red rhodamine derivatives. This result demonstrates that the labeling strategy matters and can greatly influence the duration of super-resolution imaging.

A ratiometric and colorimetric probe for detecting Hg2+ based on naphthalimide-rhodamine and its staining function in cell imaging.

In this work, a rhodamine derivative was developed as a colorimetric and ratiometric fluorescent probe for Hg2+. It exhibited a highly sensitive fluorescence response toward Hg2+. Importantly, studies revealed that the probe could be used for ratiometric detection of Hg2+, with a low detection limit of 0.679 μM. The mechanism of Hg2+ detection using compound 1 was confirmed by ESI-MS, 1H NMR, and HPLC. Upon the addition of Hg2+, the rhodamine receptor was induced to be in the ring-opening form via an Hg2+-promoted hydrolysis of rhodamine hydrazide to rhodamine acid. In addition to Hg2+ detection, the naphthalimide–rhodamine compound was proven to be effective in cell imaging.

Rhodamine-modified fluorescent half-sandwich iridium and ruthenium complexes: potential application as bioimaging and anticancer agents.

Most half-sandwich metal anticancer complexes are non-fluorescent, which results in an uncertain mechanism of action (MoA). We designed and synthesized eight fluorescent half-sandwich iridium (Ir) and ruthenium (Ru) complexes by introducing rhodamine derivatives into the N^N-chelating ligand. These complexes have features of bio-imaging and anticancer agents and may merit future development as novel anticancer agents.

Silica-embedded CdTe quantum dots functionalized with rhodamine derivative for instant visual detection of ferric ions in aqueous media

A novel hydrophilic ratiometric fluorescence sensor for instant visual detection of Fe3+ was successfully prepared by integrating silica-embedded CdTe quantum dots (QDs) with rhodamine derivative. The rich hydrophilic group and large specific surface area of CdTe@SiO2 QDs favored the adsorption of rhodamine derivative on silica and improvement of its water solubility. The results proved that the ratiometric fluorescence sensor shows a much higher selectivity towards Fe3+ with the detection limit as low as 26.5 nM than other typical cations and anions in aqueous solution. Moreover, the fluorescence response occurs instantaneously and reaches stability less than one second. Additionally, a simple and rapid paper-based analytical device was designed for on-site and visual detection of Fe3+ in actual water samples. Hence, this study provided a good candidate for the on-site and visual sensing of Fe3+ in the environmental analysis.

Photocatalysis Enables Visible‐Light Uncaging of Bioactive Molecules in Live Cells

AbstractThe photo‐manipulation of bioactive molecules provides unique advantages due to the high temporal and spatial precision of light. The first visible‐light uncaging reaction by photocatalytic deboronative hydroxylation in live cells is now demonstrated. Using Fluorescein and Rhodamine derivatives as photocatalysts and ascorbates as reductants, transient hydrogen peroxides were generated from molecular oxygen to uncage phenol, alcohol, and amine functional groups on bioactive molecules in bacteria and mammalian cells, including neurons. This effective visible‐light uncaging reaction enabled the light‐inducible protein expression, the photo‐manipulation of membrane potentials, and the subcellular‐specific photo‐release of small molecules.

Heteroatom-substituted rhodamine dyes: Structure and spectroscopic properties

Rhodamine is one class of most popular dyes used in fluorescence imaging due to the outstanding photoproperties including high brightness and photostability. In recent years, replacement the xanthene oxygen with other elements, especially silicon, has attracted great attentions in the development of new rhodamine derivatives. This review summarized the structures and photophysical properties of heteroatom-substituted rhodamines. We hope this review can help to understand the structure-property relationships of rhodamine dyes and then elucidate the way to create derivatives with improved photoproperties.

Photocatalysis Enables Visible-Light Uncaging of Bioactive Molecules in Live Cells.

The photo-manipulation of bioactive molecules provides unique advantages due to the high temporal and spatial precision of light. The first visible-light uncaging reaction by photocatalytic deboronative hydroxylation in live cells is now demonstrated. Using Fluorescein and Rhodamine derivatives as photocatalysts and ascorbates as reductants, transient hydrogen peroxides were generated from molecular oxygen to uncage phenol, alcohol, and amine functional groups on bioactive molecules in bacteria and mammalian cells, including neurons. This effective visible-light uncaging reaction enabled the light-inducible protein expression, the photo-manipulation of membrane potentials, and the subcellular-specific photo-release of small molecules.

Water-Dispersible Rhodamine B Hydrazide Loaded TiO₂ Nanoparticles for "Turn On" Fluorimetric Detection and Imaging of Orthosilicic Acid Accumulation In-Vitro in Nephrotoxic Kidney Cells.

Silica (SiO2) is the inevitable form of silicon owing to its high affinity for oxygen, existing as a geogenic element perpetrating multifarious health problems when bioavailable via anthropogenic activities. The hydrated form of silica viz. orthosilicic acid (H4SiO4) excessively displays grave toxicity, attributed to prolonged exposure and incessant H+ ions generating capacity inflicting pulmonary toxicity and renal toxicity silica. The diverse deleterious potency of silica highlights the desirability of selective and sensitive detection of toxic species (mainly orthosilicic acid) bioaccumulation in affected living human cells. In this paper we have reported, the design of water-dispersible turn-on fluorimetric sensing material for the detection of orthosilicic acid in the aqueous phase and in live cells. The sensing material was prepared by adsorbing a suitable rhodamine derivative (i.e., Rhodamine B hydrazide (Rh1)) on water dispersible TiO2 nanoparticles. The function of the sensing system, which is composed of Rh1 and TiO2 (Rh1@TiO2), is accredited to H+ ion (from orthosilicic acid) induced spirolactam ring-opening of the rhodamine derivative generating orange fluorescence and bright pink colouration. The sensing system was efficiently utilized for fluorimetric detection and imaging of orthosilicic acid accumulation in-vitro in human kidney cells (HK cells). To the best of our knowledge, this is the first time this sensing system (Rh1@TiO2) is reported for detection of toxic silica species accumulation in-vitro in human kidney cells. The advantages, such as good water dispersibility, the absence of organic solvents during fluorimetric studies, quick turn-on type signal transduction, low-level imaging, which are offered by the synthesized sensing material (Rh1@TiO2), make it a potential candidate to fabricate medical tool for early identification of silicainduced nephrotoxicity, which can help to reduce the burden and risk of chronic kidney disease development.

Rhodamine derivatives bearing thiourea groups serve as fluorescent probes for selective detection of ATP in mitochondria and lysosomes

ATP functions as an energy source in all living things and it also plays key roles in a variety of important biological processes. Moreover, low levels of ATP are indicators of cardiovascular disease, Parkinson’s disease and ischemia. As a result, the development of fluorescent probes that detect ATP selectively is a significant goal. In the current study, we synthesized two new rhodamine derivatives, 1 and 2, bearing thiourea groups, and assessed their abilities to serve as selective fluorescent and colorimetric probes for ATP. Thiourea groups were incorporated in 1 and 2 to act as hydrogen bonding donors to recognize tris-phosphate groups and induce photophysical property changing, spirocyclic ring opening. Indeed, we observed that solutions of these probes undergo a large fluorescent enhancement at 590 nm and a distinct colorimetric change from colorless to dark pink upon addition of ATP. Moreover, these probes can be used to image ATP in HeLa cells. Because it was found to locate mainly in mitochondria, 2 can be employed to image ATP in mitochondria. On the other hand, probe 1, bearing a lysosome directing morpholine group displays moderately selective localization in lysosomes and can be utilized to image ATP in lysosomes. Furthermore, both probes were shown to have extremely low cytotoxicities by using MTT assays.

Rhodamine based NIR and ratiometric fluorescent sensor for selective identification of potassium ion: application in biological sample

ABSTRACTFabrication of near infrared (NIR) and ratiometric chemosensors is very challenging task in supramolecular chemistry. For apprehension of such sensor, in the present manuscript, a thiourea derivative of rhodamine 1 is synthesized and characterized using 1H, 13C NMR and mass spectrometry. Further organic nanoparticles (N1) are fabricated from receptor 1 by reprecipitation method. Upon interaction of N1 with K(I) ion, a new peak appeared at 678 nm with concomitant decrease of peak at 555 nm and thus it acted as ratiometric and NIR fluorescent probe; whereas with other metal ions there is no such appearance of peak. The binding of K(I) ion with N1 was confirmed with titrations with lowest detection limit of 36.86 nM. Further the applicability of N1 for K(I) ion was checked on real biological samples.

Redox switchable rhodamine-ferrocene dyad: Exploring imaging possibilities in cells

An original redox-responsive fluorescent probe combining a rhodamine derivative and a ferrocenyl moiety used as the fluorescence modulator was designed, synthesized and characterized. The fluorescence of this new dyad could be tuned from the redox state of ferrocene, a feature observed both electrochemically and on cancer cells incubated with this probe.

Non-Condon Effects in the Resonance Hyper-Raman Scattering of Chalcogen-Substituted Rhodamine Derivatives

Molecules with a strong two-photon response have gained significant interest because of their applications in two-photon imaging, all-optical switching, and energy up-conversion. The surface-enhanced hyper-Raman scattering (SEHRS) of tetramethyl chalcogenorosamines are taken on- and off-resonance and compared to time-dependent density functional theory calculations. Specifically, changes in the SEHRS spectra are tracked as a function of structural geometry because of perturbations induced by larger chalcogen atom substitutions to the xanthene ring. Here we show that the spectral changes and non-Condon effects can be understood by tracking the vibrational normal modes and the vibrationally induced changes to the highest occupied molecular orbitals. With a system in place to explore the relationship between structural geometry and nonlinear properties, various rhodamine derivatives can be characterized as a means to optimally design a series of two-photon bright compounds.

New dual colorimetric/fluorimetric probes for Hg2+ detection & extraction based on mesoporous SBA-16 nanoparticles containing porphyrin or rhodamine chromophores

Multifunctional luminescent nanomaterials based on mesoporous silica SBA-16 doped with a ring-opening rhodamine derivative (RhNHS) or with a cationic porphyrin bearing imidazolium substituents (Porph) were successfully obtained and characterized. The non-immobilized Porph leads to a selective colorimetric detection for Cu2+, Pb2+ and Hg2+ in HEPES buffer at pH 7, producing colour changes from violet to pink, green and brown, detecting the minimal amount of 3.6, 5.8 and 3.8 ppm by absorption, respectively. The new approach afforded solid-state devices that showed a colorimetric and fluorometric response towards toxic metal ions, such as Cu2+, Pb2+ and Hg2+, with a naked-eye detection of 5 ppm for SBA-16@Porph. A minimal detectable amount of 2 ppb, confirmed by ICP-AES, was achieved with both hybrid nanosystems for Hg2+, and extraction values of Hg2+ in water were higher than 70%. Moreover, SBA-16@Porph was successfully applied for Hg2+ remediation in water, being able to extract the amount of 69 mg/g (0.86 mmol/g).

MicroRNAs delivery into human cells grown on 3D-printed PLA scaffolds coated with a novel fluorescent PAMAM dendrimer for biomedical applications

Many advanced synthetic, natural, degradable or non-degradable materials have been employed to create scaffolds for cell culture for biomedical or tissue engineering applications. One of the most versatile material is poly-lactide (PLA), commonly used as 3D printing filament. Manufacturing of multifunctional scaffolds with improved cell growth proliferation and able to deliver oligonucleotides represents an innovative strategy for controlled and localized gene modulation that hold great promise and could increase the number of applications in biomedicine. Here we report for the first time the synthesis of a novel Rhodamine derivative of a poly-amidoamine dendrimer (G = 5) able to transfect cells and to be monitored by confocal microscopy that we also employed to coat a 3D-printed PLA scaffold. The coating do not modify the oligonucleotide binding ability, toxicity or transfection properties of the scaffold that is able to increase cell proliferation and deliver miRNA mimics (i.e., pre-mir-503) into human cells. Although further experiments are required to optimize the dendrimer/miRNA ratio and improve transfection efficiency, we demonstrated the effectiveness of this promising and innovative 3D-printed transfection system to transfer miRNAs into human cells for future biomedical applications.